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class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Appearance </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class="">Donate</a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Domain+Name+System" title="You are encouraged to create an account and log in; however, it is not mandatory" class="">Create account</a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Domain+Name+System" title="You're encouraged to log in; however, it's not mandatory. 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[o]" accesskey="o"> Log in</a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing">learn more</a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y">Contributions</a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n">Talk</a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Function" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Function"> <div class="vector-toc-text"> 1 Function </div> </a> <ul id="toc-Function-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> 2 History </div> </a> <ul id="toc-History-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Structure" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Structure"> <div class="vector-toc-text"> 3 Structure </div> </a> <button aria-controls="toc-Structure-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Structure subsection </button> <ul id="toc-Structure-sublist" class="vector-toc-list"> <li id="toc-Domain_name_space" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Domain_name_space"> <div class="vector-toc-text"> 3.1 Domain name space </div> </a> <ul id="toc-Domain_name_space-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Domain_name_syntax,_internationalization" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Domain_name_syntax,_internationalization"> <div class="vector-toc-text"> 3.2 Domain name syntax, internationalization </div> </a> <ul id="toc-Domain_name_syntax,_internationalization-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Name_servers" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Name_servers"> <div class="vector-toc-text"> 3.3 Name servers </div> </a> <ul id="toc-Name_servers-sublist" class="vector-toc-list"> <li id="toc-Authoritative_name_server" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Authoritative_name_server"> <div class="vector-toc-text"> 3.3.1 Authoritative name server </div> </a> <ul id="toc-Authoritative_name_server-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> </ul> </li> <li id="toc-Operation" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Operation"> <div class="vector-toc-text"> 4 Operation </div> </a> <button aria-controls="toc-Operation-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Operation subsection </button> <ul id="toc-Operation-sublist" class="vector-toc-list"> <li id="toc-Address_resolution_mechanism" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Address_resolution_mechanism"> <div class="vector-toc-text"> 4.1 Address resolution mechanism </div> </a> <ul id="toc-Address_resolution_mechanism-sublist" class="vector-toc-list"> <li id="toc-Recursive_and_caching_name_server" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Recursive_and_caching_name_server"> <div class="vector-toc-text"> 4.1.1 Recursive and caching name server </div> </a> <ul id="toc-Recursive_and_caching_name_server-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-DNS_resolvers" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DNS_resolvers"> <div class="vector-toc-text"> 4.2 DNS resolvers </div> </a> <ul id="toc-DNS_resolvers-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Circular_dependencies_and_glue_records" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Circular_dependencies_and_glue_records"> <div class="vector-toc-text"> 4.3 Circular dependencies and glue records </div> </a> <ul id="toc-Circular_dependencies_and_glue_records-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Record_caching" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Record_caching"> <div class="vector-toc-text"> 4.4 Record caching </div> </a> <ul id="toc-Record_caching-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Reverse_lookup" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Reverse_lookup"> <div class="vector-toc-text"> 4.5 Reverse lookup </div> </a> <ul id="toc-Reverse_lookup-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Client_lookup" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Client_lookup"> <div class="vector-toc-text"> 4.6 Client lookup </div> </a> <ul id="toc-Client_lookup-sublist" class="vector-toc-list"> <li id="toc-Broken_resolvers" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Broken_resolvers"> <div class="vector-toc-text"> 4.6.1 Broken resolvers </div> </a> <ul id="toc-Broken_resolvers-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Other_applications" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_applications"> <div class="vector-toc-text"> 4.7 Other applications </div> </a> <ul id="toc-Other_applications-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-DNS_message_format" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#DNS_message_format"> <div class="vector-toc-text"> 5 DNS message format </div> </a> <button aria-controls="toc-DNS_message_format-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle DNS message format subsection </button> <ul id="toc-DNS_message_format-sublist" class="vector-toc-list"> <li id="toc-Question_section" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Question_section"> <div class="vector-toc-text"> 5.1 Question section </div> </a> <ul id="toc-Question_section-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Resource_records" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Resource_records"> <div class="vector-toc-text"> 6 Resource records </div> </a> <button aria-controls="toc-Resource_records-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Resource records subsection </button> <ul id="toc-Resource_records-sublist" class="vector-toc-list"> <li id="toc-Wildcard_records" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Wildcard_records"> <div class="vector-toc-text"> 6.1 Wildcard records </div> </a> <ul id="toc-Wildcard_records-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Protocol_extensions" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Protocol_extensions"> <div class="vector-toc-text"> 7 Protocol extensions </div> </a> <ul id="toc-Protocol_extensions-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Dynamic_zone_updates" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Dynamic_zone_updates"> <div class="vector-toc-text"> 8 Dynamic zone updates </div> </a> <ul id="toc-Dynamic_zone_updates-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Transport_protocols" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Transport_protocols"> <div class="vector-toc-text"> 9 Transport protocols </div> </a> <button aria-controls="toc-Transport_protocols-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Transport protocols subsection </button> <ul id="toc-Transport_protocols-sublist" class="vector-toc-list"> <li id="toc-DNS_over_UDP/TCP/53_(Do53)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DNS_over_UDP/TCP/53_(Do53)"> <div class="vector-toc-text"> 9.1 DNS over UDP/TCP/53 (Do53) </div> </a> <ul id="toc-DNS_over_UDP/TCP/53_(Do53)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-DNS_over_TLS_(DoT)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DNS_over_TLS_(DoT)"> <div class="vector-toc-text"> 9.2 DNS over TLS (DoT) </div> </a> <ul id="toc-DNS_over_TLS_(DoT)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-DNS_over_HTTPS_(DoH)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DNS_over_HTTPS_(DoH)"> <div class="vector-toc-text"> 9.3 DNS over HTTPS (DoH) </div> </a> <ul id="toc-DNS_over_HTTPS_(DoH)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-DNS_over_QUIC_(DoQ)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DNS_over_QUIC_(DoQ)"> <div class="vector-toc-text"> 9.4 DNS over QUIC (DoQ) </div> </a> <ul id="toc-DNS_over_QUIC_(DoQ)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Oblivious_DoH_(ODoH)_and_predecessor_Oblivious_DNS_(ODNS)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Oblivious_DoH_(ODoH)_and_predecessor_Oblivious_DNS_(ODNS)"> <div class="vector-toc-text"> 9.5 Oblivious DoH (ODoH) and predecessor Oblivious DNS (ODNS) </div> </a> <ul id="toc-Oblivious_DoH_(ODoH)_and_predecessor_Oblivious_DNS_(ODNS)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-DNS_over_Tor" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DNS_over_Tor"> <div class="vector-toc-text"> 9.6 DNS over Tor </div> </a> <ul id="toc-DNS_over_Tor-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-DNSCrypt" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DNSCrypt"> <div class="vector-toc-text"> 9.7 DNSCrypt </div> </a> <ul id="toc-DNSCrypt-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Security_issues" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Security_issues"> <div class="vector-toc-text"> 10 Security issues </div> </a> <ul id="toc-Security_issues-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Privacy_and_tracking_issues" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Privacy_and_tracking_issues"> <div class="vector-toc-text"> 11 Privacy and tracking issues </div> </a> <ul id="toc-Privacy_and_tracking_issues-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Domain_name_registration" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Domain_name_registration"> <div class="vector-toc-text"> 12 Domain name registration </div> </a> <ul id="toc-Domain_name_registration-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> 13 See also </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> 14 References </div> </a> <button aria-controls="toc-References-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle References subsection </button> <ul id="toc-References-sublist" class="vector-toc-list"> <li id="toc-Sources" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Sources"> <div class="vector-toc-text"> 14.1 Sources </div> </a> <ul id="toc-Sources-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> 15 Further reading </div> </a> <button aria-controls="toc-Further_reading-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Further reading subsection </button> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> <li id="toc-Standards_track" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Standards_track"> <div class="vector-toc-text"> 15.1 Standards track </div> </a> <ul id="toc-Standards_track-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Proposed_security_standards" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Proposed_security_standards"> <div class="vector-toc-text"> 15.2 Proposed security standards </div> </a> <ul id="toc-Proposed_security_standards-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Experimental_RFCs" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Experimental_RFCs"> <div class="vector-toc-text"> 15.3 Experimental RFCs </div> </a> <ul id="toc-Experimental_RFCs-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Best_Current_Practices" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Best_Current_Practices"> <div class="vector-toc-text"> 15.4 Best Current Practices </div> </a> <ul id="toc-Best_Current_Practices-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Informational_RFCs" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Informational_RFCs"> <div class="vector-toc-text"> 15.5 Informational RFCs </div> </a> <ul id="toc-Informational_RFCs-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Unknown" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Unknown"> <div class="vector-toc-text"> 15.6 Unknown </div> </a> <ul id="toc-Unknown-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> 16 External links </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Toggle the table of contents </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading">Domain Name System</h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 80 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-80" aria-hidden="true" > 80 languages </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Domeinnaamstelsel" title="Domeinnaamstelsel – Afrikaans" lang="af" hreflang="af" data-title="Domeinnaamstelsel" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target">Afrikaans</a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%86%D8%B8%D8%A7%D9%85_%D8%A3%D8%B3%D9%85%D8%A7%D8%A1_%D8%A7%D9%84%D9%86%D8%B7%D8%A7%D9%82%D8%A7%D8%AA" title="نظام أسماء النطاقات – Arabic" lang="ar" hreflang="ar" data-title="نظام أسماء النطاقات" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target">العربية</a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Sistema_de_nomes_de_dominiu" title="Sistema de nomes de dominiu – Asturian" lang="ast" hreflang="ast" data-title="Sistema de nomes de dominiu" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target">Asturianu</a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Azerbaijani" lang="az" hreflang="az" data-title="Domain Name System" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target">Azərbaycanca</a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%A1%E0%A7%8B%E0%A6%AE%E0%A7%87%E0%A6%87%E0%A6%A8_%E0%A6%A8%E0%A7%87%E0%A6%AE_%E0%A6%B8%E0%A6%BF%E0%A6%B8%E0%A7%8D%E0%A6%9F%E0%A7%87%E0%A6%AE" title="ডোমেইন নেম সিস্টেম – Bangla" lang="bn" hreflang="bn" data-title="ডোমেইন নেম সিস্টেম" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target">বাংলা</a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Minnan" lang="nan" hreflang="nan" data-title="Domain Name System" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="Minnan" class="interlanguage-link-target">閩南語 / Bân-lâm-gú</a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/DNS" title="DNS – Belarusian" lang="be" hreflang="be" data-title="DNS" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target">Беларуская</a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/DNS" title="DNS – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="DNS" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target">Беларуская (тарашкевіца)</a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Bulgarian" lang="bg" hreflang="bg" data-title="Domain Name System" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target">Български</a></li><li class="interlanguage-link interwiki-bar mw-list-item"><a href="https://bar.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Bavarian" lang="bar" hreflang="bar" data-title="Domain Name System" data-language-autonym="Boarisch" data-language-local-name="Bavarian" class="interlanguage-link-target">Boarisch</a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Bosnian" lang="bs" hreflang="bs" data-title="Domain Name System" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target">Bosanski</a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Catalan" lang="ca" hreflang="ca" data-title="Domain Name System" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target">Català</a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Czech" lang="cs" hreflang="cs" data-title="Domain Name System" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target">Čeština</a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Danish" lang="da" hreflang="da" data-title="Domain Name System" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target">Dansk</a></li><li class="interlanguage-link interwiki-ary mw-list-item"><a href="https://ary.wikipedia.org/wiki/%D8%B3%D9%8A%D8%B3%D8%B7%D9%8A%D9%85_%D8%AA%D8%A7%D8%B9_%D8%B3%D9%85%D9%8A%D8%A7%D8%AA_%D8%A7%D9%84%D8%B6%D9%88%D9%85%D9%8A%D9%86%D8%A7%D8%AA" title="سيسطيم تاع سميات الضومينات – Moroccan Arabic" lang="ary" hreflang="ary" data-title="سيسطيم تاع سميات الضومينات" data-language-autonym="الدارجة" data-language-local-name="Moroccan Arabic" class="interlanguage-link-target">الدارجة</a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – German" lang="de" hreflang="de" data-title="Domain Name System" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target">Deutsch</a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Domeeninimede_s%C3%BCsteem" title="Domeeninimede süsteem – Estonian" lang="et" hreflang="et" data-title="Domeeninimede süsteem" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target">Eesti</a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A3%CF%8D%CF%83%CF%84%CE%B7%CE%BC%CE%B1_%CE%9F%CE%BD%CE%BF%CE%BC%CE%B1%CF%84%CE%BF%CE%B4%CE%BF%CF%83%CE%AF%CE%B1%CF%82_%CE%94%CE%B9%CE%B1%CE%B4%CE%B9%CE%BA%CF%84%CF%8D%CE%BF%CF%85" title="Σύστημα Ονοματοδοσίας Διαδικτύου – Greek" lang="el" hreflang="el" data-title="Σύστημα Ονοματοδοσίας Διαδικτύου" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target">Ελληνικά</a></li><li class="interlanguage-link interwiki-eml mw-list-item"><a href="https://eml.wikipedia.org/wiki/Dom%C3%ACni_(inform%C3%A0tica)" title="Domìni (informàtica) – Emiliano-Romagnolo" lang="egl" hreflang="egl" data-title="Domìni (informàtica)" data-language-autonym="Emiliàn e rumagnòl" data-language-local-name="Emiliano-Romagnolo" class="interlanguage-link-target">Emiliàn e rumagnòl</a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Sistema_de_nombres_de_dominio" title="Sistema de nombres de dominio – Spanish" lang="es" hreflang="es" data-title="Sistema de nombres de dominio" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target">Español</a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Domajna_nomsistemo" title="Domajna nomsistemo – Esperanto" lang="eo" hreflang="eo" data-title="Domajna nomsistemo" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target">Esperanto</a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Basque" lang="eu" hreflang="eu" data-title="Domain Name System" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target">Euskara</a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B3%D8%A7%D9%85%D8%A7%D9%86%D9%87_%D9%86%D8%A7%D9%85_%D8%AF%D8%A7%D9%85%D9%86%D9%87" title="سامانه نام دامنه – Persian" lang="fa" hreflang="fa" data-title="سامانه نام دامنه" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target">فارسی</a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – French" lang="fr" hreflang="fr" data-title="Domain Name System" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target">Français</a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Galician" lang="gl" hreflang="gl" data-title="Domain Name System" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target">Galego</a></li><li class="interlanguage-link interwiki-gu mw-list-item"><a href="https://gu.wikipedia.org/wiki/%E0%AA%A1%E0%AB%8B%E0%AA%AE%E0%AB%87%E0%AA%A8_%E0%AA%A8%E0%AA%BE%E0%AA%AE_%E0%AA%AA%E0%AB%8D%E0%AA%B0%E0%AA%A3%E0%AA%BE%E0%AA%B2%E0%AB%80" title="ડોમેન નામ પ્રણાલી – Gujarati" lang="gu" hreflang="gu" data-title="ડોમેન નામ પ્રણાલી" data-language-autonym="ગુજરાતી" data-language-local-name="Gujarati" class="interlanguage-link-target">ગુજરાતી</a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%8F%84%EB%A9%94%EC%9D%B8_%EB%84%A4%EC%9E%84_%EC%8B%9C%EC%8A%A4%ED%85%9C" title="도메인 네임 시스템 – Korean" lang="ko" hreflang="ko" data-title="도메인 네임 시스템" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target">한국어</a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/DNS" title="DNS – Armenian" lang="hy" hreflang="hy" data-title="DNS" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target">Հայերեն</a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%A1%E0%A5%8B%E0%A4%AE%E0%A5%87%E0%A4%A8_%E0%A4%A8%E0%A4%BE%E0%A4%AE_%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%A3%E0%A4%BE%E0%A4%B2%E0%A5%80" title="डोमेन नाम प्रणाली – Hindi" lang="hi" hreflang="hi" data-title="डोमेन नाम प्रणाली" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target">हिन्दी</a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Sustav_domenskih_imena" title="Sustav domenskih imena – Croatian" lang="hr" hreflang="hr" data-title="Sustav domenskih imena" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target">Hrvatski</a></li><li class="interlanguage-link interwiki-io mw-list-item"><a href="https://io.wikipedia.org/wiki/Sistemo_di_domeno-nomi" title="Sistemo di domeno-nomi – Ido" lang="io" hreflang="io" data-title="Sistemo di domeno-nomi" data-language-autonym="Ido" data-language-local-name="Ido" class="interlanguage-link-target">Ido</a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Sistem_Penamaan_Domain" title="Sistem Penamaan Domain – Indonesian" lang="id" hreflang="id" data-title="Sistem Penamaan Domain" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target">Bahasa Indonesia</a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Nafna%C3%BEj%C3%B3nn" title="Nafnaþjónn – Icelandic" lang="is" hreflang="is" data-title="Nafnaþjónn" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target">Íslenska</a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Italian" lang="it" hreflang="it" data-title="Domain Name System" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target">Italiano</a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Hebrew" lang="he" hreflang="he" data-title="Domain Name System" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target">עברית</a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%94%D0%BE%D0%BC%D0%B5%D0%BD%D0%B4%D1%96%D0%BA_%D0%B0%D1%82%D0%B0%D1%83_%D0%B6%D2%AF%D0%B9%D0%B5%D1%81%D1%96" title="Домендік атау жүйесі – Kazakh" lang="kk" hreflang="kk" data-title="Домендік атау жүйесі" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target">Қазақша</a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%94%D0%BE%D0%BC%D0%B5%D0%BD_%D0%B0%D1%82%D0%B0%D0%BB%D1%8B%D1%88%D1%82%D0%B0%D1%80_%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC%D0%B0%D1%81%D1%8B" title="Домен аталыштар системасы – Kyrgyz" lang="ky" hreflang="ky" data-title="Домен аталыштар системасы" data-language-autonym="Кыргызча" data-language-local-name="Kyrgyz" class="interlanguage-link-target">Кыргызча</a></li><li class="interlanguage-link interwiki-ltg mw-list-item"><a href="https://ltg.wikipedia.org/wiki/Mui%C5%BEvuordu_sistema" title="Muižvuordu sistema – Latgalian" lang="ltg" hreflang="ltg" data-title="Muižvuordu sistema" data-language-autonym="Latgaļu" data-language-local-name="Latgalian" class="interlanguage-link-target">Latgaļu</a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/DNS_(protokols)" title="DNS (protokols) – Latvian" lang="lv" hreflang="lv" data-title="DNS (protokols)" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target">Latviešu</a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/DNS" title="DNS – Lithuanian" lang="lt" hreflang="lt" data-title="DNS" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target">Lietuvių</a></li><li class="interlanguage-link interwiki-li mw-list-item"><a href="https://li.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Limburgish" lang="li" hreflang="li" data-title="Domain Name System" data-language-autonym="Limburgs" data-language-local-name="Limburgish" class="interlanguage-link-target">Limburgs</a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Lombard" lang="lmo" hreflang="lmo" data-title="Domain Name System" data-language-autonym="Lombard" data-language-local-name="Lombard" class="interlanguage-link-target">Lombard</a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Hungarian" lang="hu" hreflang="hu" data-title="Domain Name System" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target">Magyar</a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%94%D0%BE%D0%BC%D0%B5%D0%BD%D1%81%D0%BA%D0%B8_%D0%B8%D0%BC%D0%B5%D0%BD%D1%81%D0%BA%D0%B8_%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC" title="Доменски именски систем – Macedonian" lang="mk" hreflang="mk" data-title="Доменски именски систем" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target">Македонски</a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%A1%E0%B5%8A%E0%B4%AE%E0%B5%86%E0%B4%AF%E0%B4%BF%E0%B5%BB_%E0%B4%A8%E0%B5%86%E0%B4%AF%E0%B4%BF%E0%B4%82_%E0%B4%B8%E0%B4%BF%E0%B4%B8%E0%B5%8D%E0%B4%B1%E0%B5%8D%E0%B4%B1%E0%B4%82" title="ഡൊമെയിൻ നെയിം സിസ്റ്റം – Malayalam" lang="ml" hreflang="ml" data-title="ഡൊമെയിൻ നെയിം സിസ്റ്റം" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target">മലയാളം</a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Sistem_Nama_Domain" title="Sistem Nama Domain – Malay" lang="ms" hreflang="ms" data-title="Sistem Nama Domain" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target">Bahasa Melayu</a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%94%D0%BE%D0%BC%D1%8D%D0%B9%D0%BD_%D0%BD%D1%8D%D1%80%D0%B8%D0%B9%D0%BD_%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC" title="Домэйн нэрийн систем – Mongolian" lang="mn" hreflang="mn" data-title="Домэйн нэрийн систем" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target">Монгол</a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Dutch" lang="nl" hreflang="nl" data-title="Domain Name System" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target">Nederlands</a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Japanese" lang="ja" hreflang="ja" data-title="Domain Name System" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target">日本語</a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Domain Name System" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target">Norsk bokmål</a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/DNS" title="DNS – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="DNS" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target">Norsk nynorsk</a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Sist%C3%A8ma_de_noms_de_domeni" title="Sistèma de noms de domeni – Occitan" lang="oc" hreflang="oc" data-title="Sistèma de noms de domeni" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target">Occitan</a></li><li class="interlanguage-link interwiki-mhr mw-list-item"><a href="https://mhr.wikipedia.org/wiki/DNS" title="DNS – Eastern Mari" lang="mhr" hreflang="mhr" data-title="DNS" data-language-autonym="Олык марий" data-language-local-name="Eastern Mari" class="interlanguage-link-target">Олык марий</a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Polish" lang="pl" hreflang="pl" data-title="Domain Name System" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target">Polski</a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Sistema_de_Nomes_de_Dom%C3%ADnio" title="Sistema de Nomes de Domínio – Portuguese" lang="pt" hreflang="pt" data-title="Sistema de Nomes de Domínio" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target">Português</a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Romanian" lang="ro" hreflang="ro" data-title="Domain Name System" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target">Română</a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/DNS" title="DNS – Russian" lang="ru" hreflang="ru" data-title="DNS" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target">Русский</a></li><li class="interlanguage-link interwiki-sah mw-list-item"><a href="https://sah.wikipedia.org/wiki/DNS" title="DNS – Yakut" lang="sah" hreflang="sah" data-title="DNS" data-language-autonym="Саха тыла" data-language-local-name="Yakut" class="interlanguage-link-target">Саха тыла</a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Sistemi_i_Emrave_t%C3%AB_Domen%C3%ABve" title="Sistemi i Emrave të Domenëve – Albanian" lang="sq" hreflang="sq" data-title="Sistemi i Emrave të Domenëve" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target">Shqip</a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Simple English" lang="en-simple" hreflang="en-simple" data-title="Domain Name System" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target">Simple English</a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Syst%C3%A9m_n%C3%A1zvov_dom%C3%A9n" title="Systém názvov domén – Slovak" lang="sk" hreflang="sk" data-title="Systém názvov domén" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target">Slovenčina</a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/DNS" title="DNS – Slovenian" lang="sl" hreflang="sl" data-title="DNS" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target">Slovenščina</a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D8%B3%DB%8C%D8%B3%D8%AA%D9%85%DB%8C_%D9%86%D8%A7%D9%88%DB%8C_%D9%BE%D8%A7%D9%88%D8%A7%D9%86" title="سیستمی ناوی پاوان – Central Kurdish" lang="ckb" hreflang="ckb" data-title="سیستمی ناوی پاوان" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target">کوردی</a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%A1%D0%B8%D1%81%D1%82%D0%B5%D0%BC_%D0%B8%D0%BC%D0%B5%D0%BD%D0%B0_%D0%B4%D0%BE%D0%BC%D0%B5%D0%BD%D0%B0" title="Систем имена домена – Serbian" lang="sr" hreflang="sr" data-title="Систем имена домена" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target">Српски / srpski</a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/DNS" title="DNS – Serbo-Croatian" lang="sh" hreflang="sh" data-title="DNS" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target">Srpskohrvatski / српскохрватски</a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/DNS" title="DNS – Finnish" lang="fi" hreflang="fi" data-title="DNS" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target">Suomi</a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Dom%C3%A4nnamnssystemet" title="Domännamnssystemet – Swedish" lang="sv" hreflang="sv" data-title="Domännamnssystemet" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target">Svenska</a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%95%E0%AE%B3%E0%AE%AA%E0%AF%8D_%E0%AE%AA%E0%AF%86%E0%AE%AF%E0%AE%B0%E0%AF%8D_%E0%AE%AE%E0%AF%81%E0%AE%B1%E0%AF%88%E0%AE%AE%E0%AF%88" title="களப் பெயர் முறைமை – Tamil" lang="ta" hreflang="ta" data-title="களப் பெயர் முறைமை" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target">தமிழ்</a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%A1%E0%B1%8A%E0%B0%AE%E0%B1%88%E0%B0%A8%E0%B1%8D_%E0%B0%A8%E0%B1%87%E0%B0%AE%E0%B1%8D_%E0%B0%B8%E0%B0%BF%E0%B0%B8%E0%B1%8D%E0%B0%9F%E0%B0%AE%E0%B1%8D" title="డొమైన్ నేమ్ సిస్టమ్ – Telugu" lang="te" hreflang="te" data-title="డొమైన్ నేమ్ సిస్టమ్" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target">తెలుగు</a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%94%E0%B8%B5%E0%B9%80%E0%B8%AD%E0%B9%87%E0%B8%99%E0%B9%80%E0%B8%AD%E0%B8%AA" title="ดีเอ็นเอส – Thai" lang="th" hreflang="th" data-title="ดีเอ็นเอส" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target">ไทย</a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/DNS" title="DNS – Turkish" lang="tr" hreflang="tr" data-title="DNS" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target">Türkçe</a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A1%D0%B8%D1%81%D1%82%D0%B5%D0%BC%D0%B0_%D0%B4%D0%BE%D0%BC%D0%B5%D0%BD%D0%BD%D0%B8%D1%85_%D1%96%D0%BC%D0%B5%D0%BD" title="Система доменних імен – Ukrainian" lang="uk" hreflang="uk" data-title="Система доменних імен" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target">Українська</a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D9%86%D8%B8%D8%A7%D9%85_%DA%88%D9%88%D9%85%DB%8C%D9%86_%D9%86%DB%8C%D9%85" title="نظام ڈومین نیم – Urdu" lang="ur" hreflang="ur" data-title="نظام ڈومین نیم" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target">اردو</a></li><li class="interlanguage-link interwiki-vec 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class="interlanguage-link-target">吴语</a></li><li class="interlanguage-link interwiki-yi mw-list-item"><a href="https://yi.wikipedia.org/wiki/DNS" title="DNS – Yiddish" lang="yi" hreflang="yi" data-title="DNS" data-language-autonym="ייִדיש" data-language-local-name="Yiddish" class="interlanguage-link-target">ייִדיש</a></li><li class="interlanguage-link interwiki-yo mw-list-item"><a href="https://yo.wikipedia.org/wiki/Domain_Name_System" title="Domain Name System – Yoruba" lang="yo" hreflang="yo" data-title="Domain Name System" data-language-autonym="Yorùbá" data-language-local-name="Yoruba" class="interlanguage-link-target">Yorùbá</a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/DNS" title="DNS – Cantonese" lang="yue" hreflang="yue" data-title="DNS" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target">粵語</a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a 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<div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">System to identify resources on a network</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">"DNS" redirects here. For other uses, see <a href="/wiki/DNS_(disambiguation)" class="mw-disambig" title="DNS (disambiguation)">DNS (disambiguation)</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist 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href="/wiki/Internet_protocol_suite" title="Internet protocol suite">Internet protocol suite</a></th></tr><tr><th class="sidebar-heading"> <a href="/wiki/Application_layer" title="Application layer">Application layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol">BGP</a></li> <li><a href="/wiki/Dynamic_Host_Configuration_Protocol" title="Dynamic Host Configuration Protocol">DHCP</a> (<a href="/wiki/DHCPv6" title="DHCPv6">v6</a>)</li> <li><a class="mw-selflink selflink">DNS</a></li> <li><a href="/wiki/File_Transfer_Protocol" title="File Transfer Protocol">FTP</a></li> <li><a href="/wiki/HTTP" title="HTTP">HTTP</a> (<a href="/wiki/HTTP/3" title="HTTP/3">HTTP/3</a>)</li> <li><a href="/wiki/HTTPS" title="HTTPS">HTTPS</a></li> <li><a href="/wiki/Internet_Message_Access_Protocol" title="Internet Message Access Protocol">IMAP</a></li> <li><a href="/wiki/IRC" title="IRC">IRC</a></li> <li><a href="/wiki/Lightweight_Directory_Access_Protocol" title="Lightweight Directory Access Protocol">LDAP</a></li> <li><a href="/wiki/Media_Gateway_Control_Protocol" title="Media Gateway Control Protocol">MGCP</a></li> <li><a href="/wiki/MQTT" title="MQTT">MQTT</a></li> <li><a href="/wiki/Network_News_Transfer_Protocol" title="Network News Transfer Protocol">NNTP</a></li> <li><a href="/wiki/Network_Time_Protocol" title="Network Time Protocol">NTP</a></li> <li><a href="/wiki/Open_Shortest_Path_First" title="Open Shortest Path First">OSPF</a></li> <li><a href="/wiki/Post_Office_Protocol" title="Post Office Protocol">POP</a></li> <li><a href="/wiki/Precision_Time_Protocol" title="Precision Time Protocol">PTP</a></li> <li><a href="/wiki/Open_Network_Computing_Remote_Procedure_Call" class="mw-redirect" title="Open Network Computing Remote Procedure Call">ONC/RPC</a></li> <li><a href="/wiki/Real-time_Transport_Protocol" title="Real-time Transport Protocol">RTP</a></li> <li><a href="/wiki/Real_Time_Streaming_Protocol" class="mw-redirect" title="Real Time Streaming Protocol">RTSP</a></li> <li><a href="/wiki/Routing_Information_Protocol" title="Routing Information Protocol">RIP</a></li> <li><a href="/wiki/Session_Initiation_Protocol" title="Session Initiation Protocol">SIP</a></li> <li><a href="/wiki/Simple_Mail_Transfer_Protocol" title="Simple Mail Transfer Protocol">SMTP</a></li> <li><a href="/wiki/Simple_Network_Management_Protocol" title="Simple Network Management Protocol">SNMP</a></li> <li><a href="/wiki/Secure_Shell" title="Secure Shell">SSH</a></li> <li><a href="/wiki/Telnet" title="Telnet">Telnet</a></li> <li><a href="/wiki/Transport_Layer_Security" title="Transport Layer Security">TLS/SSL</a></li> <li><a href="/wiki/XMPP" title="XMPP">XMPP</a></li> <li><a href="/wiki/Category:Application_layer_protocols" title="Category:Application layer protocols">more...</a></li></ul></td> </tr><tr><th class="sidebar-heading"> <a href="/wiki/Transport_layer" title="Transport layer">Transport layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Transmission_Control_Protocol" title="Transmission Control Protocol">TCP</a></li> <li><a href="/wiki/User_Datagram_Protocol" title="User Datagram Protocol">UDP</a></li> <li><a href="/wiki/Datagram_Congestion_Control_Protocol" title="Datagram Congestion Control Protocol">DCCP</a></li> <li><a href="/wiki/Stream_Control_Transmission_Protocol" title="Stream Control Transmission Protocol">SCTP</a></li> <li><a href="/wiki/Resource_Reservation_Protocol" title="Resource Reservation Protocol">RSVP</a></li> <li><a href="/wiki/QUIC" title="QUIC">QUIC</a></li> <li><a href="/wiki/Category:Transport_layer_protocols" title="Category:Transport layer protocols">more...</a></li></ul></td> </tr><tr><th class="sidebar-heading"> <a href="/wiki/Internet_layer" title="Internet layer">Internet layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Internet_Protocol" title="Internet Protocol">IP</a> <ul><li><a href="/wiki/IPv4" title="IPv4">v4</a></li> <li><a href="/wiki/IPv6" title="IPv6">v6</a></li></ul></li> <li><a href="/wiki/Internet_Control_Message_Protocol" title="Internet Control Message Protocol">ICMP</a> (<a href="/wiki/ICMPv6" title="ICMPv6">v6</a>)</li> <li><a href="/wiki/Neighbor_Discovery_Protocol" title="Neighbor Discovery Protocol">NDP</a></li> <li><a href="/wiki/Explicit_Congestion_Notification" title="Explicit Congestion Notification">ECN</a></li> <li><a href="/wiki/Internet_Group_Management_Protocol" title="Internet Group Management Protocol">IGMP</a></li> <li><a href="/wiki/IPsec" title="IPsec">IPsec</a></li> <li><a href="/wiki/Category:Internet_layer_protocols" title="Category:Internet layer protocols">more...</a></li></ul></td> </tr><tr><th class="sidebar-heading"> <a href="/wiki/Link_layer" title="Link layer">Link layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Address_Resolution_Protocol" title="Address Resolution Protocol">ARP</a></li> <li><a href="/wiki/Tunneling_protocol" title="Tunneling protocol">Tunnels</a></li> <li><a href="/wiki/Point-to-Point_Protocol" title="Point-to-Point Protocol">PPP</a></li> <li><a href="/wiki/Medium_access_control" title="Medium access control">MAC</a></li> <li><a href="/wiki/Category:Link_protocols" title="Category:Link protocols">more...</a></li></ul></td> </tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Internet_protocol_suite" title="Template:Internet protocol suite"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Internet_protocol_suite" title="Template talk:Internet protocol suite"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Internet_protocol_suite" title="Special:EditPage/Template:Internet protocol suite"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <table cellpadding="1" class="mw-collapsible mw-collapsed" style="width: 220px; float: right; clear: right; border: 1px solid #8888aa; padding: 5px; margin: 0 0 15px 15px; text-align: left;"> <tbody><tr> <td style="background: #ccf; text-align: center;">Internet history timeline </td></tr> <tr> <td> Early research and development: <ul><li>1960–4 (1960–4): <a href="/wiki/RAND" class="mw-redirect" title="RAND">RAND</a> networking concepts developed</li> <li>1962–4 (1962–4): <a href="/wiki/DARPA" title="DARPA">ARPA</a> networking ideas</li> <li>1965 (1965): <a href="/wiki/NPL_network" title="NPL network">NPL network</a> concepts conceived</li> <li>1966 (1966): <a href="/wiki/Merit_Network" title="Merit Network">Merit Network</a> founded</li> <li>1967 (1967): <a href="/wiki/ARPANET" title="ARPANET">ARPANET</a> planning begins</li> <li>1967 (1967): <a href="/wiki/Symposium_on_Operating_Systems_Principles" title="Symposium on Operating Systems Principles">Symposium on Operating Systems Principles</a></li> <li>1969 (1969): NPL followed by the ARPANET carry their first packets</li> <li>1970 (1970): <a href="/wiki/InterNIC#History" title="InterNIC">Network Information Center</a> (NIC)</li> <li>1971 (1971): <a href="/wiki/Tymnet" title="Tymnet">Tymnet</a> switched-circuit network</li> <li>1972 (1972): Merit Network's packet-switched network operational</li> <li>1972 (1972): <a href="/wiki/Internet_Assigned_Numbers_Authority" title="Internet Assigned Numbers Authority">Internet Assigned Numbers Authority</a> (IANA) established</li> <li>1973 (1973): <a href="/wiki/CYCLADES" title="CYCLADES">CYCLADES</a> network demonstrated</li> <li>1973 (1973): <a href="/wiki/PARC_Universal_Packet" title="PARC Universal Packet">PARC Universal Packet</a> development begins</li> <li>1974 (1974): <a href="/wiki/Transmission_Control_Program" class="mw-redirect" title="Transmission Control Program">Transmission Control Program</a> specification published</li> <li>1975 (1975): <a href="/wiki/Telenet" title="Telenet">Telenet</a> commercial packet-switched network</li> <li>1976 (1976): <a href="/wiki/X.25" title="X.25">X.25</a> protocol approved and deployed on <a href="/wiki/Public_data_network" title="Public data network">public data networks</a></li> <li>1978 (1978): <a href="/wiki/Minitel" title="Minitel">Minitel</a> introduced</li> <li>1979 (1979): <a href="/wiki/Internet_Architecture_Board" title="Internet Architecture Board">Internet Activities Board</a> (IAB)</li> <li>1980 (1980): <a href="/wiki/Usenet" title="Usenet">USENET</a> news using <a href="/wiki/UUCP" title="UUCP">UUCP</a></li> <li>1980 (1980): <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a> standard introduced</li> <li>1981 (1981): <a href="/wiki/BITNET" title="BITNET">BITNET</a> established</li></ul> Merging the networks and creating the Internet: <ul><li>1981 (1981): <a href="/wiki/CSNET" title="CSNET">Computer Science Network</a> (CSNET)</li> <li>1982 (1982): <a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">TCP/IP</a> protocol suite formalized</li> <li>1982 (1982): <a href="/wiki/Simple_Mail_Transfer_Protocol" title="Simple Mail Transfer Protocol">Simple Mail Transfer Protocol</a> (SMTP)</li> <li>1983 (1983): <a class="mw-selflink selflink">Domain Name System</a> (DNS)</li> <li>1983 (1983): <a href="/wiki/MILNET" title="MILNET">MILNET</a> split off from ARPANET</li> <li>1984 (1984): <a href="/wiki/OSI_model" title="OSI model">OSI Reference Model</a> released</li> <li>1985 (1985): <a href="/wiki/Domain_names#Domain_name_registration" class="mw-redirect" title="Domain names">First .COM domain name registered</a></li> <li>1986 (1986): <a href="/wiki/National_Science_Foundation_Network" title="National Science Foundation Network">NSFNET</a> with 56 kbit/s links</li> <li>1986 (1986): <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">Internet Engineering Task Force</a> (IETF)</li> <li>1987 (1987): <a href="/wiki/UUNET" title="UUNET">UUNET</a> founded</li> <li>1988 (1988): <a href="/wiki/National_Science_Foundation_Network" title="National Science Foundation Network">NSFNET</a> upgraded to 1.5 Mbit/s (T1)</li> <li>1988 (1988): <a href="/wiki/Morris_worm" title="Morris worm">Morris worm</a></li> <li>1988 (1988): Complete <a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">Internet protocol suite</a></li> <li>1989 (1989): <a href="/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol">Border Gateway Protocol</a> (BGP)</li> <li>1989 (1989): <a href="/wiki/PSINet" title="PSINet">PSINet</a> founded, allows commercial traffic</li> <li>1989 (1989): <a href="/wiki/Federal_Internet_Exchange" title="Federal Internet Exchange">Federal Internet Exchanges (FIX East|FIXes)</a></li> <li>1990 (1990): <a href="/wiki/Government_Open_Systems_Interconnection_Profile" title="Government Open Systems Interconnection Profile">GOSIP</a> (without <a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">TCP/IP</a>)</li> <li>1990 (1990): ARPANET decommissioned</li> <li>1990 (1990): <a href="/wiki/Advanced_Network_and_Services" title="Advanced Network and Services">Advanced Network and Services</a> (ANS)</li> <li>1990 (1990): <a href="/wiki/UUNET#Early_existence" title="UUNET">UUNET/Alternet</a> allows commercial traffic</li> <li>1990 (1990): <a href="/wiki/Archie_(search_engine)" title="Archie (search engine)">Archie search engine</a></li> <li>1991 (1991): <a href="/wiki/Wide_area_information_server" title="Wide area information server">Wide area information server</a> (WAIS)</li> <li>1991 (1991): <a href="/wiki/Gopher_(protocol)" title="Gopher (protocol)">Gopher</a></li> <li>1991 (1991): <a href="/wiki/Commercial_Internet_eXchange" title="Commercial Internet eXchange">Commercial Internet eXchange</a> (CIX)</li> <li>1991 (1991): <a href="/wiki/Advanced_Network_and_Services" title="Advanced Network and Services">ANS CO+RE</a> allows commercial traffic</li> <li>1991 (1991): <a href="/wiki/World_Wide_Web" title="World Wide Web">World Wide Web</a> (WWW)</li> <li>1992 (1992): <a href="/wiki/National_Science_Foundation_Network" title="National Science Foundation Network">NSFNET</a> upgraded to 45 Mbit/s (T3)</li> <li>1992 (1992): <a href="/wiki/Internet_Society" title="Internet Society">Internet Society</a> (ISOC) established</li> <li>1993 (1993): <a href="/wiki/Classless_Inter-Domain_Routing" title="Classless Inter-Domain Routing">Classless Inter-Domain Routing</a> (CIDR)</li> <li>1993 (1993): <a href="/wiki/InterNIC" title="InterNIC">InterNIC</a> established</li> <li>1993 (1993): <a href="/wiki/AOL" title="AOL">AOL</a> added <a href="/wiki/Usenet" title="Usenet">USENET</a> access</li> <li>1993 (1993): <a href="/wiki/NCSA_Mosaic" title="NCSA Mosaic">Mosaic web browser</a> released</li> <li>1994 (1994): <a href="/wiki/Search_engine" title="Search engine">Full text web search engines</a></li> <li>1994 (1994): <a href="/wiki/North_American_Network_Operators%27_Group" title="North American Network Operators' Group">North American Network Operators' Group</a> (NANOG) established</li></ul> Commercialization, privatization, broader access leads to the modern Internet: <ul><li>1995 (1995): New Internet architecture with commercial <a href="/wiki/Internet_service_provider" title="Internet service provider">ISPs</a> connected at <a href="/wiki/Network_Access_Point" class="mw-redirect" title="Network Access Point">NAPs</a></li> <li>1995 (1995): <a href="/wiki/National_Science_Foundation_Network" title="National Science Foundation Network">NSFNET</a> decommissioned</li> <li>1995 (1995): <a href="/wiki/GOSIP" class="mw-redirect" title="GOSIP">GOSIP</a> updated to allow <a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">TCP/IP</a></li> <li>1995 (1995): <a href="/wiki/Very_high-speed_Backbone_Network_Service" title="Very high-speed Backbone Network Service">very high-speed Backbone Network Service (vBNS)</a></li> <li>1995 (1995): <a href="/wiki/IPv6" title="IPv6">IPv6</a> proposed</li> <li>1996 (1996): <a href="/wiki/AOL" title="AOL">AOL</a> changes pricing model from hourly to monthly</li> <li>1998 (1998): <a href="/wiki/ICANN" title="ICANN">Internet Corporation for Assigned Names and Numbers (ICANN)</a></li> <li>1999 (1999): <a href="/wiki/IEEE_802.11" title="IEEE 802.11">IEEE 802.11b</a> wireless networking</li> <li>1999 (1999): <a href="/wiki/Internet2" title="Internet2">Internet2</a>/<a href="/wiki/Abilene_Network" title="Abilene Network">Abilene Network</a></li> <li>1999 (1999): <a href="/wiki/VBNS" class="mw-redirect" title="VBNS">vBNS+</a> allows broader access</li> <li>2000 (2000): <a href="/wiki/Dot-com_bubble" title="Dot-com bubble">Dot-com bubble</a> bursts</li> <li>2001 (2001): <a href="/wiki/Top-level_domain#Proposed_domains" title="Top-level domain">New top-level domain names activated</a></li> <li>2001 (2001): <a href="/wiki/Code_Red_(computer_worm)" title="Code Red (computer worm)">Code Red I</a>, <a href="/wiki/Code_Red_II" title="Code Red II">Code Red II</a>, and <a href="/wiki/Nimda" title="Nimda">Nimda</a> worms</li> <li>2003 (2003): <a href="/wiki/World_Summit_on_the_Information_Society" title="World Summit on the Information Society">UN World Summit on the Information Society (WSIS) phase I</a></li></ul> <ul><li>2003 (2003): <a href="/wiki/National_LambdaRail" title="National LambdaRail">National LambdaRail</a> founded</li> <li>2004 (2004): <a href="/wiki/Working_Group_on_Internet_Governance" title="Working Group on Internet Governance">UN Working Group on Internet Governance (WGIG)</a></li> <li>2005 (2005): <a href="/wiki/World_Summit_on_the_Information_Society" title="World Summit on the Information Society">UN WSIS phase II</a></li> <li>2006 (2006): <a href="/wiki/Internet_Governance_Forum" title="Internet Governance Forum">First meeting of the Internet Governance Forum</a></li> <li>2010 (2010): <a href="/wiki/Top-level_domain#Internationalized_country_code_TLDs" title="Top-level domain">First internationalized country code top-level domains</a> registered</li> <li>2012 (2012): <a href="/wiki/Generic_top-level_domain#New_top-level_domains" title="Generic top-level domain">ICANN begins accepting applications for new generic top-level domain names</a></li> <li>2013 (2013): <a href="/wiki/Montevideo_Statement_on_the_Future_of_Internet_Cooperation" title="Montevideo Statement on the Future of Internet Cooperation">Montevideo Statement on the Future of Internet Cooperation</a></li> <li>2014 (2014): <a href="/wiki/NetMundial_Initiative" title="NetMundial Initiative">NetMundial international Internet governance proposal</a></li> <li>2016 (2016): <a href="/wiki/ICANN" title="ICANN">ICANN</a> contract with U.S. Dept. of Commerce ends, <a href="/wiki/Internet_Assigned_Numbers_Authority" title="Internet Assigned Numbers Authority">IANA</a> oversight passes to the global Internet community on October 1st</li></ul> Examples of Internet services: <ul><li>1989 (1989): <a href="/wiki/AOL" title="AOL">AOL</a> dial-up service provider, email, instant messaging, and web browser</li> <li>1990 (1990): <a href="/wiki/IMDb" title="IMDb">IMDb</a> Internet movie database</li> <li>1994 (1994): <a href="/wiki/Yahoo" title="Yahoo">Yahoo!</a> web directory</li> <li>1995 (1995): <a href="/wiki/Amazon_(company)" title="Amazon (company)">Amazon</a> online retailer</li> <li>1995 (1995): <a href="/wiki/EBay" title="EBay">eBay</a> online auction and shopping</li> <li>1995 (1995): <a href="/wiki/Craigslist" title="Craigslist">Craigslist</a> classified advertisements</li> <li>1995 (1995): <a href="/wiki/AltaVista" title="AltaVista">AltaVista</a> search engine</li> <li>1996 (1996): <a href="/wiki/Outlook.com" title="Outlook.com">Outlook (formerly Hotmail)</a> free web-based e-mail</li> <li>1996 (1996): <a href="/wiki/Baidu" title="Baidu">RankDex</a> search engine</li> <li>1997 (1997): <a href="/wiki/Google_Search" title="Google Search">Google Search</a></li> <li>1997 (1997): <a href="/wiki/Babel_Fish_(website)" title="Babel Fish (website)">Babel Fish</a> automatic translation</li> <li>1998 (1998): <a href="/wiki/Yahoo_Groups" title="Yahoo Groups">Yahoo Groups (formerly Yahoo! Clubs)</a></li> <li>1998 (1998): <a href="/wiki/PayPal" title="PayPal">PayPal</a> Internet payment system</li> <li>1998 (1998): <a href="/wiki/Rotten_Tomatoes" title="Rotten Tomatoes">Rotten Tomatoes</a> review aggregator</li> <li>1999 (1999): <a href="/wiki/2channel" title="2channel">2ch</a> Anonymous textboard</li> <li>1999 (1999): <a href="/wiki/I-mode" title="I-mode">i-mode</a> mobile internet service</li> <li>1999 (1999): <a href="/wiki/Napster" title="Napster">Napster</a> peer-to-peer file sharing</li> <li>2000 (2000): <a href="/wiki/Baidu" title="Baidu">Baidu</a> search engine</li> <li>2001 (2001): <a href="/wiki/Futaba_Channel" title="Futaba Channel">2chan</a> Anonymous imageboard</li> <li>2001 (2001): <a href="/wiki/BitTorrent_(software)" title="BitTorrent (software)">BitTorrent</a> peer-to-peer file sharing</li> <li>2001 (2001): <a href="/wiki/Wikipedia" title="Wikipedia">Wikipedia</a>, the free encyclopedia</li> <li>2003 (2003): <a href="/wiki/LinkedIn" title="LinkedIn">LinkedIn</a> business networking</li> <li>2003 (2003): <a href="/wiki/Myspace" title="Myspace">Myspace</a> social networking site</li> <li>2003 (2003): <a href="/wiki/Skype" title="Skype">Skype</a> Internet voice calls</li> <li>2003 (2003): <a href="/wiki/ITunes_Store" title="ITunes Store">iTunes Store</a></li> <li>2003 (2003): <a href="/wiki/4chan" title="4chan">4chan</a> Anonymous imageboard</li> <li>2003 (2003): <a href="/wiki/The_Pirate_Bay" title="The Pirate Bay">The Pirate Bay</a>, <a href="/wiki/Torrent_file" title="Torrent file">torrent file</a> host</li> <li>2004 (2004): <a href="/wiki/Facebook" title="Facebook">Facebook</a> social networking site</li> <li>2004 (2004): <a href="/wiki/Podcast" title="Podcast">Podcast</a> media file series</li> <li>2004 (2004): <a href="/wiki/Flickr" title="Flickr">Flickr</a> image hosting</li> <li>2005 (2005): <a href="/wiki/YouTube" title="YouTube">YouTube</a> video sharing</li> <li>2005 (2005): <a href="/wiki/Reddit" title="Reddit">Reddit</a> link voting</li> <li>2005 (2005): <a href="/wiki/Google_Earth" title="Google Earth">Google Earth</a> virtual globe</li> <li>2006 (2006): <a href="/wiki/Twitter" title="Twitter">Twitter</a> microblogging</li> <li>2007 (2007): <a href="/wiki/WikiLeaks" title="WikiLeaks">WikiLeaks</a> anonymous news and information leaks</li> <li>2007 (2007): <a href="/wiki/Google_Street_View" title="Google Street View">Google Street View</a></li> <li>2007 (2007): <a href="/wiki/Amazon_Kindle" title="Amazon Kindle">Kindle</a>, <a href="/wiki/E-reader" title="E-reader">e-reader</a> and virtual bookshop</li> <li>2008 (2008): <a href="/wiki/Amazon_Elastic_Compute_Cloud" title="Amazon Elastic Compute Cloud">Amazon Elastic Compute Cloud</a> (EC2)</li> <li>2008 (2008): <a href="/wiki/Dropbox" title="Dropbox">Dropbox</a> cloud-based file hosting</li> <li>2008 (2008): <a href="/wiki/Encyclopedia_of_Life" title="Encyclopedia of Life">Encyclopedia of Life</a>, a collaborative encyclopedia intended to document all living species</li> <li>2008 (2008): <a href="/wiki/Spotify" title="Spotify">Spotify</a>, a <a href="/wiki/Digital_rights_management" title="Digital rights management">DRM-based</a> music streaming service</li> <li>2009 (2009): <a href="/wiki/Microsoft_Bing" title="Microsoft Bing">Bing</a> search engine</li> <li>2009 (2009): <a href="/wiki/Google_Docs" title="Google Docs">Google Docs</a>, Web-based word processor, spreadsheet, presentation, form, and data storage service</li> <li>2009 (2009): <a href="/wiki/Kickstarter" title="Kickstarter">Kickstarter</a>, a <a href="/wiki/Threshold_pledge_system" title="Threshold pledge system">threshold pledge system</a></li> <li>2009 (2009): <a href="/wiki/Bitcoin" title="Bitcoin">Bitcoin</a>, a <a href="/wiki/Digital_currency" title="Digital currency">digital currency</a></li> <li>2010 (2010): <a href="/wiki/Instagram" title="Instagram">Instagram</a>, <a href="/wiki/Photo_sharing" class="mw-redirect" title="Photo sharing">photo sharing</a> and <a href="/wiki/Social_networking" class="mw-redirect" title="Social networking">social networking</a></li> <li>2011 (2011): <a href="/wiki/Google%2B" title="Google+">Google+</a>, <a href="/wiki/Social_networking" class="mw-redirect" title="Social networking">social networking</a></li> <li>2011 (2011): <a href="/wiki/Snapchat" title="Snapchat">Snapchat</a>, <a href="/wiki/Photo_sharing" class="mw-redirect" title="Photo sharing">photo sharing</a></li> <li>2012 (2012): <a href="/wiki/Coursera" title="Coursera">Coursera</a>, massive open online courses</li> <li>2016 (2016): <a href="/wiki/TikTok" title="TikTok">TikTok</a>, <a href="/wiki/Video_sharing" class="mw-redirect" title="Video sharing">video sharing</a> and <a href="/wiki/Social_networking" class="mw-redirect" title="Social networking">social networking</a></li></ul> </td></tr></tbody></table> The Domain Name System (DNS) is a hierarchical and distributed <a href="/wiki/Name_service" class="mw-redirect" title="Name service">name service</a> that provides a naming system for <a href="/wiki/Computer" title="Computer">computers</a>, services, and other resources on the Internet or other <a href="/wiki/Internet_Protocol" title="Internet Protocol">Internet Protocol</a> (IP) networks. It associates various information with <a href="/wiki/Domain_name" title="Domain name">domain names</a> (<a href="/wiki/Identification_(information)" title="Identification (information)">identification</a> <a href="/wiki/String_(computer_science)" title="String (computer science)">strings</a>) assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical <a href="/wiki/IP_address" title="IP address">IP addresses</a> needed for locating and identifying computer services and devices with the underlying <a href="/wiki/Network_protocol" class="mw-redirect" title="Network protocol">network protocols</a>.<a href="#cite_note-1">[1]</a> The Domain Name System has been an essential component of the functionality of the Internet since 1985. The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating <a href="/wiki/Authoritative_name_server" class="mw-redirect" title="Authoritative name server">authoritative name servers</a> for each domain. Network administrators may delegate authority over <a href="/wiki/Subdomain" title="Subdomain">subdomains</a> of their allocated name space to other name servers. This mechanism provides distributed and <a href="/wiki/Fault-tolerant" class="mw-redirect" title="Fault-tolerant">fault-tolerant</a> service and was designed to avoid a single large central database. In addition, the DNS specifies the technical functionality of the <a href="/wiki/Database_model" title="Database model">database</a> service that is at its core. It defines the DNS protocol, a detailed specification of the data structures and data communication exchanges used in the DNS, as part of the <a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">Internet protocol suite</a>. The Internet maintains two principal <a href="/wiki/Namespace" title="Namespace">namespaces</a>, the domain name hierarchy and the IP <a href="/wiki/Address_space" title="Address space">address spaces</a>.<a href="#cite_note-rfc781-2">[2]</a> The Domain Name System maintains the domain name hierarchy and provides translation services between it and the address spaces. Internet name servers and a <a href="/wiki/Communication_protocol" title="Communication protocol">communication protocol</a> implement the Domain Name System. A DNS name server is a server that stores the DNS records for a domain; a DNS name server responds with answers to queries against its database. The most common types of records stored in the DNS database are for start of authority (<a href="/wiki/SOA_record" title="SOA record">SOA</a>), IP addresses (<a href="/wiki/List_of_DNS_record_types#A" title="List of DNS record types">A</a> and <a href="/wiki/AAAA_record" class="mw-redirect" title="AAAA record">AAAA</a>), <a href="/wiki/SMTP" class="mw-redirect" title="SMTP">SMTP</a> <a href="/wiki/Mail_exchanger" class="mw-redirect" title="Mail exchanger">mail exchangers</a> (MX), name servers (NS), pointers for <a href="/wiki/Reverse_DNS_lookup" title="Reverse DNS lookup">reverse DNS lookups</a> (PTR), and <a href="/wiki/Domain_name_alias" class="mw-redirect" title="Domain name alias">domain name aliases</a> (CNAME). Although not intended to be a general purpose database, DNS has been expanded over time to store records for other types of data for either automatic lookups, such as <a href="/wiki/DNSSEC" class="mw-redirect" title="DNSSEC">DNSSEC</a> records, or for human queries such as responsible person (RP) records. As a general purpose database, the DNS has also been used in combating <a href="/wiki/Unsolicited_email" class="mw-redirect" title="Unsolicited email">unsolicited email</a> (spam) by storing a <a href="/wiki/Real-time_blackhole_list" class="mw-redirect" title="Real-time blackhole list">real-time blackhole list</a> (RBL). The DNS database is traditionally stored in a structured text file, the <a href="/wiki/Zone_file" title="Zone file">zone file</a>, but other database systems are common. The Domain Name System originally used the <a href="/wiki/User_Datagram_Protocol" title="User Datagram Protocol">User Datagram Protocol</a> (UDP) as transport over IP. Reliability, security, and privacy concerns spawned the use of the <a href="/wiki/Transmission_Control_Protocol" title="Transmission Control Protocol">Transmission Control Protocol</a> (TCP) as well as numerous other protocol developments. <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Function">Function</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=1" title="Edit section: Function">edit</a>]</div> An often-used analogy to explain the DNS is that it serves as the <a href="/wiki/Telephone_directory" title="Telephone directory">phone book</a> for the Internet by translating human-friendly computer <a href="/wiki/Hostname" title="Hostname">hostnames</a> into IP addresses. For example, the hostname <code>www.example.com</code> within the domain name <a href="/wiki/Example.com" title="Example.com">example.com</a> translates to the addresses 93.184.216.34 (<a href="/wiki/IPv4" title="IPv4">IPv4</a>) and 2606:2800:220:1:248:1893:25c8:1946 (<a href="/wiki/IPv6" title="IPv6">IPv6</a>). The DNS can be quickly and transparently updated, allowing a service's location on the network to change without affecting the end users, who continue to use the same hostname. Users take advantage of this when they use meaningful Uniform Resource Locators (<a href="/wiki/URL" title="URL">URLs</a>) and <a href="/wiki/E-mail_address" class="mw-redirect" title="E-mail address">e-mail addresses</a> without having to know how the computer actually locates the services. An important and <a href="/wiki/Ubiquitous_computing" title="Ubiquitous computing">ubiquitous</a> function of the DNS is its central role in distributed Internet services such as <a href="/wiki/Cloud_service" class="mw-redirect" title="Cloud service">cloud services</a> and <a href="/wiki/Content_delivery_network" title="Content delivery network">content delivery networks</a>.<a href="#cite_note-3">[3]</a> When a user accesses a distributed Internet service using a URL, the domain name of the <a href="/wiki/URL" title="URL">URL</a> is translated to the IP address of a server that is proximal to the user. The key functionality of the DNS exploited here is that different users can simultaneously receive different translations for the same domain name, a key point of divergence from a traditional phone-book view of the DNS. This process of using the DNS to assign proximal servers to users is key to providing faster and more reliable responses on the Internet and is widely used by most major Internet services.<a href="#cite_note-4">[4]</a> The DNS reflects the structure of administrative responsibility on the Internet.<a href="#cite_note-rfc1035-5">[5]</a> Each subdomain is a <a href="/wiki/DNS_zone" title="DNS zone">zone</a> of administrative autonomy delegated to a manager. For zones operated by a <a href="/wiki/Domain_name_registry" title="Domain name registry">registry</a>, administrative information is often complemented by the registry's <a href="/wiki/Registration_Data_Access_Protocol" title="Registration Data Access Protocol">RDAP</a> and <a href="/wiki/WHOIS" title="WHOIS">WHOIS</a> services. That data can be used to gain insight on, and track responsibility for, a given host on the Internet.<a href="#cite_note-6">[6]</a> <div class="mw-heading mw-heading2"><h2 id="History">History</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=2" title="Edit section: History">edit</a>]</div> Using a simpler, more memorable name in place of a host's numerical address dates back to the <a href="/wiki/ARPANET" title="ARPANET">ARPANET</a> era. The Stanford Research Institute (now <a href="/wiki/SRI_International" title="SRI International">SRI International</a>) maintained a text file named <a href="/wiki/Hosts_(file)" title="Hosts (file)">HOSTS.TXT</a> that mapped host names to the numerical addresses of computers on the ARPANET.<a href="#cite_note-rfc3467-7">[7]</a><a href="#cite_note-8">[8]</a> <a href="/wiki/Elizabeth_J._Feinler" title="Elizabeth J. Feinler">Elizabeth Feinler</a> developed and maintained the first ARPANET directory.<a href="#cite_note-FOOTNOTEEvans2018112-9">[9]</a><a href="#cite_note-FOOTNOTEEvans2018113-10">[10]</a> Maintenance of numerical addresses, called the Assigned Numbers List, was handled by <a href="/wiki/Jon_Postel" title="Jon Postel">Jon Postel</a> at the <a href="/wiki/University_of_Southern_California" title="University of Southern California">University of Southern California</a>'s <a href="/wiki/Information_Sciences_Institute" title="Information Sciences Institute">Information Sciences Institute</a> (ISI), whose team worked closely with SRI.<a href="#cite_note-11">[11]</a> Addresses were assigned manually. Computers, including their hostnames and addresses, were added to the primary file by contacting the SRI <a href="/wiki/InterNIC" title="InterNIC">Network Information Center</a> (NIC), directed by Feinler, via <a href="/wiki/Telephone" title="Telephone">telephone</a> during business hours.<a href="#cite_note-internethalloffame.org-12">[12]</a> Later, Feinler set up a <a href="/wiki/WHOIS" title="WHOIS">WHOIS</a> directory on a server in the NIC for retrieval of information about resources, contacts, and entities.<a href="#cite_note-FOOTNOTEEvans2018119-13">[13]</a> She and her team developed the concept of domains.<a href="#cite_note-FOOTNOTEEvans2018119-13">[13]</a> Feinler suggested that domains should be based on the location of the physical address of the computer.<a href="#cite_note-FOOTNOTEEvans2018120-14">[14]</a> Computers at educational institutions would have the domain <a href="/wiki/.edu" title=".edu">edu</a>, for example.<a href="#cite_note-FOOTNOTEEvans2018120–121-15">[15]</a> She and her team managed the Host Naming Registry from 1972 to 1989.<a href="#cite_note-16">[16]</a> By the early 1980s, maintaining a single, centralized host table had become slow and unwieldy and the emerging network required an automated naming system to address technical and personnel issues. Postel directed the task of forging a compromise between five competing proposals of solutions to <a href="/wiki/Paul_Mockapetris" title="Paul Mockapetris">Paul Mockapetris</a>. Mockapetris instead created the Domain Name System in 1983 while at the <a href="/wiki/University_of_Southern_California" title="University of Southern California">University of Southern California</a>.<a href="#cite_note-internethalloffame.org-12">[12]</a><a href="#cite_note-17">[17]</a> The <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">Internet Engineering Task Force</a> published the original specifications in RFC 882 and RFC 883 in November 1983.<a href="#cite_note-18">[18]</a><a href="#cite_note-19">[19]</a> These were updated in RFC 973 in January 1986. In 1984, four <a href="/wiki/University_of_California,_Berkeley" title="University of California, Berkeley">UC Berkeley</a> students, Douglas Terry, Mark Painter, David Riggle, and Songnian Zhou, wrote the first <a href="/wiki/Unix" title="Unix">Unix</a> <a href="/wiki/Name_server" title="Name server">name server</a> implementation for the Berkeley Internet Name Domain, commonly referred to as <a href="/wiki/BIND" title="BIND">BIND</a>.<a href="#cite_note-Terry_USENIX_2004-20">[20]</a> In 1985, Kevin Dunlap of <a href="/wiki/Digital_Equipment_Corporation" title="Digital Equipment Corporation">DEC</a> substantially revised the DNS implementation. <a href="/wiki/Michael_J._Karels" title="Michael J. Karels">Mike Karels</a>, Phil Almquist, and <a href="/wiki/Paul_Vixie" title="Paul Vixie">Paul Vixie</a> then took over BIND maintenance. <a href="/wiki/Internet_Systems_Consortium" title="Internet Systems Consortium">Internet Systems Consortium</a> was founded in 1994 by <a href="/wiki/Rick_Adams_(Internet_pioneer)" title="Rick Adams (Internet pioneer)">Rick Adams</a>, <a href="/wiki/Paul_Vixie" title="Paul Vixie">Paul Vixie</a>, and <a href="/wiki/Carl_Malamud" title="Carl Malamud">Carl Malamud</a>, expressly to provide a home for BIND development and maintenance. BIND versions from 4.9.3 onward were developed and maintained by ISC, with support provided by ISC's sponsors. As co-architects/programmers, Bob Halley and Paul Vixie released the first production-ready version of BIND version 8 in May 1997. Since 2000, over 43 different core developers have worked on BIND.<a href="#cite_note-BIND_Home_Page-21">[21]</a> In November 1987, RFC 1034<a href="#cite_note-rfc1034-22">[22]</a> and RFC 1035<a href="#cite_note-rfc1035-5">[5]</a> superseded the 1983 DNS specifications. Several additional <a href="/wiki/Request_for_Comments" title="Request for Comments">Request for Comments</a> have proposed extensions to the core DNS protocols.<a href="#cite_note-rfc7719-23">[23]</a> <div class="mw-heading mw-heading2"><h2 id="Structure">Structure </h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=3" title="Edit section: Structure">edit</a>]</div> <div class="mw-heading mw-heading3"><h3 id="Domain_name_space">Domain name space</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=4" title="Edit section: Domain name space">edit</a>]</div> The domain name space consists of a <a href="/wiki/Tree_(data_structure)" class="mw-redirect" title="Tree (data structure)">tree data structure</a>. Each node or leaf in the tree has a label and zero or more resource records (RR), which hold information associated with the domain name. The domain name itself consists of the label, concatenated with the name of its parent node on the right, separated by a dot.<a href="#cite_note-dnsterms-24">[24]</a> The tree sub-divides into zones beginning at the <a href="/wiki/DNS_root_zone" title="DNS root zone">root zone</a>. A <a href="/wiki/DNS_zone" title="DNS zone">DNS zone</a> may consist of as many domains and subdomains as the zone manager chooses. DNS can also be partitioned according to class where the separate classes can be thought of as an array of parallel namespace trees.<a href="#cite_note-dnsparts-25">[25]</a> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Domain_name_space.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Domain_name_space.svg/400px-Domain_name_space.svg.png" decoding="async" width="400" height="319" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Domain_name_space.svg/600px-Domain_name_space.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Domain_name_space.svg/800px-Domain_name_space.svg.png 2x" data-file-width="675" data-file-height="538" /></a><figcaption>The hierarchical Domain Name System for class Internet, organized into zones, each served by a name server</figcaption></figure> Administrative responsibility for any zone may be divided by creating additional zones. Authority over the new zone is said to be delegated to a designated name server. The parent zone ceases to be authoritative for the new zone.<a href="#cite_note-dnsparts-25">[25]</a> <div class="mw-heading mw-heading3"><h3 id="Domain_name_syntax,_internationalization">Domain name syntax, internationalization</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=5" title="Edit section: Domain name syntax, internationalization">edit</a>]</div> The definitive descriptions of the rules for forming domain names appear in RFC 1035, RFC 1123, RFC 2181, and RFC 5892. A <a href="/wiki/Domain_name" title="Domain name">domain name</a> consists of one or more parts, technically called labels, that are conventionally <a href="/wiki/Concatenated" class="mw-redirect" title="Concatenated">concatenated</a>, and delimited by dots, such as example.com. The right-most label conveys the <a href="/wiki/Top-level_domain" title="Top-level domain">top-level domain</a>; for example, the domain name www.example.com belongs to the top-level domain com. The hierarchy of domains descends from right to left; each label to the left specifies a subdivision, or <a href="/wiki/Subdomain" title="Subdomain">subdomain</a> of the domain to the right. For example, the label example specifies a subdomain of the com domain, and www is a subdomain of example.com. This tree of subdivisions may have up to 127 levels.<a href="#cite_note-26">[26]</a> A label may contain zero to 63 characters, because the length is only allowed to take 6 bits. The null label of length zero is reserved for the root zone. The full domain name may not exceed the length of 253 characters in its textual representation (or 254 with the trailing dot).<a href="#cite_note-rfc1034-22">[22]</a> In the internal binary representation of the DNS this maximum length of 253 requires 255 octets of storage, as it also stores the length of the first of many labels and adds last null byte.<a href="#cite_note-rfc1035-5">[5]</a> 255 length is only achieved with at least 6 labels (counting the last null label).[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] Although no technical limitation exists to prevent domain name labels from using any character that is representable by an octet, hostnames use a preferred format and character set. The characters allowed in labels are a subset of the <a href="/wiki/ASCII" title="ASCII">ASCII</a> character set, consisting of characters a through z, A through Z, digits 0 through 9, and hyphen. This rule is known as the LDH rule (letters, digits, hyphen). Domain names are interpreted in a case-independent manner.<a href="#cite_note-rfc4343-27">[27]</a> Labels may not start or end with a hyphen.<a href="#cite_note-rfc3696-28">[28]</a> An additional rule requires that top-level domain names should not be all-numeric.<a href="#cite_note-rfc3696-28">[28]</a> The limited set of ASCII characters permitted in the DNS prevented the representation of names and words of many languages in their native alphabets or scripts. To make this possible, <a href="/wiki/ICANN" title="ICANN">ICANN</a> approved the <a href="/wiki/Internationalized_domain_name" title="Internationalized domain name">Internationalizing Domain Names in Applications</a> (IDNA) system, by which user applications, such as web browsers, map <a href="/wiki/Unicode" title="Unicode">Unicode</a> strings into the valid DNS character set using <a href="/wiki/Punycode" title="Punycode">Punycode</a>. In 2009, ICANN approved the installation of internationalized domain name <a href="/wiki/Country_code_top-level_domain" title="Country code top-level domain">country code top-level domains (ccTLDs)</a>. In addition, many <a href="/wiki/Domain_name_registry" title="Domain name registry">registries</a> of the existing top-level domain names (<a href="/wiki/Top-level_domain" title="Top-level domain">TLDs</a>) have adopted the IDNA system, guided by RFC 5890, RFC 5891, RFC 5892, RFC 5893. <div class="mw-heading mw-heading3"><h3 id="Name_servers">Name servers</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=6" title="Edit section: Name servers">edit</a>]</div> The Domain Name System is maintained by a <a href="/wiki/Distributed_database" title="Distributed database">distributed database</a> system, which uses the <a href="/wiki/Client%E2%80%93server_model" title="Client–server model">client–server model</a>. The nodes of this database are the <a href="/wiki/Name_server" title="Name server">name servers</a>. Each domain has at least one authoritative DNS server that publishes information about that domain and the name servers of any domains subordinate to it. The top of the hierarchy is served by the <a href="/wiki/Root_name_server" title="Root name server">root name servers</a>, the servers to query when looking up (resolving) a <a href="/wiki/Top-level_domain" title="Top-level domain">TLD</a>. <div class="mw-heading mw-heading4"><h4 id="Authoritative_name_server">Authoritative name server</h4>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=7" title="Edit section: Authoritative name server">edit</a>]</div> An authoritative name server is a name server that only gives <a href="/wiki/Name_server#Authoritative_answer" title="Name server">answers</a> to DNS queries from data that have been configured by an original source, for example, the domain administrator or by dynamic DNS methods, in contrast to answers obtained via a query to another name server that only maintains a cache of data. An authoritative name server can either be a primary server or a secondary server. Historically the terms <a href="/wiki/Master/slave_(technology)" class="mw-redirect" title="Master/slave (technology)">master/slave</a> and primary/secondary were sometimes used interchangeably<a href="#cite_note-29">[29]</a> but the current practice is to use the latter form. A primary server is a server that stores the original copies of all zone records. A secondary server uses a special <a href="/wiki/AXFR" class="mw-redirect" title="AXFR">automatic updating mechanism</a> in the DNS protocol in communication with its primary to maintain an identical copy of the primary records. Every DNS zone must be assigned a set of authoritative name servers. This set of servers is stored in the parent domain zone with name server (NS) records. An authoritative server indicates its status of supplying definitive answers, deemed authoritative, by setting a protocol flag, called the "Authoritative Answer" (AA) <a href="/wiki/Bit" title="Bit">bit</a> in its responses.<a href="#cite_note-rfc1035-5">[5]</a> This flag is usually reproduced prominently in the output of DNS administration query tools, such as <a href="/wiki/Domain_Information_Groper" class="mw-redirect" title="Domain Information Groper">dig</a>, to indicate that the responding name server is an authority for the domain name in question.<a href="#cite_note-rfc1035-5">[5]</a> When a name server is designated as the authoritative server for a domain name for which it does not have authoritative data, it presents a type of error called a "lame delegation" or "lame response".<a href="#cite_note-30">[30]</a><a href="#cite_note-31">[31]</a> <div class="mw-heading mw-heading2"><h2 id="Operation">Operation</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=8" title="Edit section: Operation">edit</a>]</div> <div class="mw-heading mw-heading3"><h3 id="Address_resolution_mechanism">Address resolution mechanism</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=9" title="Edit section: Address resolution mechanism">edit</a>]</div> Domain name resolvers determine the domain name servers responsible for the domain name in question by a sequence of queries starting with the right-most (top-level) domain label. <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Example_of_an_iterative_DNS_resolver.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Example_of_an_iterative_DNS_resolver.svg/400px-Example_of_an_iterative_DNS_resolver.svg.png" decoding="async" width="400" height="142" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Example_of_an_iterative_DNS_resolver.svg/600px-Example_of_an_iterative_DNS_resolver.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Example_of_an_iterative_DNS_resolver.svg/800px-Example_of_an_iterative_DNS_resolver.svg.png 2x" data-file-width="563" data-file-height="200" /></a><figcaption>A DNS resolver that implements the iterative approach mandated by RFC 1034; in this case, the resolver consults three name servers to resolve the <a href="/wiki/Fully_qualified_domain_name" title="Fully qualified domain name">fully qualified domain name</a> "www.wikipedia.org".</figcaption></figure> For proper operation of its domain name resolver, a network host is configured with an initial cache (hints) of the known addresses of the root name servers. The hints are updated periodically by an administrator by retrieving a dataset from a reliable source. Assuming the resolver has no cached records to accelerate the process, the resolution process starts with a query to one of the root servers. In typical operation, the root servers do not answer directly, but respond with a referral to more authoritative servers, e.g., a query for "www.wikipedia.org" is referred to the org servers. The resolver now queries the servers referred to, and iteratively repeats this process until it receives an authoritative answer. The diagram illustrates this process for the host that is named by the <a href="/wiki/Fully_qualified_domain_name" title="Fully qualified domain name">fully qualified domain name</a> "www.wikipedia.org". This mechanism would place a large traffic burden on the root servers, if every resolution on the Internet required starting at the root. In practice <a href="#Record_caching">caching</a> is used in DNS servers to off-load the root servers, and as a result, root name servers actually are involved in only a relatively small fraction of all requests. <div class="mw-heading mw-heading4"><h4 id="Recursive_and_caching_name_server">Recursive and caching name server</h4>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=10" title="Edit section: Recursive and caching name server">edit</a>]</div> In theory, authoritative name servers are sufficient for the operation of the Internet. However, with only authoritative name servers operating, every DNS query must start with recursive queries at the <a href="/wiki/DNS_root_zone" title="DNS root zone">root zone</a> of the Domain Name System and each user system would have to implement resolver software capable of recursive operation.<a href="#cite_note-32">[32]</a> To improve efficiency, reduce DNS traffic across the Internet, and increase performance in end-user applications, the Domain Name System supports DNS cache servers which store DNS query results for a period of time determined in the configuration (<a href="/wiki/Time-to-live" class="mw-redirect" title="Time-to-live">time-to-live</a>) of the domain name record in question. Typically, such caching DNS servers also implement the recursive algorithm necessary to resolve a given name starting with the DNS root through to the authoritative name servers of the queried domain. With this function implemented in the name server, user applications gain efficiency in design and operation. The combination of DNS caching and recursive functions in a name server is not mandatory; the functions can be implemented independently in servers for special purposes. <a href="/wiki/Internet_service_providers" class="mw-redirect" title="Internet service providers">Internet service providers</a> typically provide recursive and caching name servers for their customers. In addition, many home networking routers implement DNS caches and recursion to improve efficiency in the local network. <div class="mw-heading mw-heading3"><h3 id="DNS_resolvers">DNS resolvers</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=11" title="Edit section: DNS resolvers">edit</a>]</div> The <a href="/wiki/Client-side" class="mw-redirect" title="Client-side">client side</a> of the DNS is called a DNS resolver. A resolver is responsible for initiating and sequencing the queries that ultimately lead to a full resolution (translation) of the resource sought, e.g., translation of a domain name into an IP address. DNS resolvers are classified by a variety of query methods, such as recursive, non-recursive, and iterative. A resolution process may use a combination of these methods.<a href="#cite_note-rfc1034-22">[22]</a> In a non-recursive query, a DNS resolver queries a DNS server that provides a record either for which the server is authoritative, or it provides a partial result without querying other servers. In case of a <a href="#Record_caching">caching DNS resolver</a>, the non-recursive query of its local <a href="/wiki/Name_server#Caching_name_server" title="Name server">DNS cache</a> delivers a result and reduces the load on upstream DNS servers by caching DNS resource records for a period of time after an initial response from upstream DNS servers. In a recursive query, a DNS resolver queries a single DNS server, which may in turn query other DNS servers on behalf of the requester. For example, a simple stub resolver running on a <a href="/wiki/Home_router" class="mw-redirect" title="Home router">home router</a> typically makes a recursive query to the DNS server run by the user's <a href="/wiki/ISP" class="mw-redirect" title="ISP">ISP</a>. A recursive query is one for which the DNS server answers the query completely by querying other name servers as needed. In typical operation, a client issues a recursive query to a caching recursive DNS server, which subsequently issues non-recursive queries to determine the answer and send a single answer back to the client. The resolver, or another DNS server acting recursively on behalf of the resolver, negotiates use of recursive service using bits in the query headers. DNS servers are not required to support recursive queries. The iterative query procedure is a process in which a DNS resolver queries a chain of one or more DNS servers. Each server refers the client to the next server in the chain, until the current server can fully resolve the request. For example, a possible resolution of www.example.com would query a global root server, then a "com" server, and finally an "example.com" server. <div class="mw-heading mw-heading3"><h3 id="Circular_dependencies_and_glue_records">Circular dependencies and glue records</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=12" title="Edit section: Circular dependencies and glue records">edit</a>]</div> Name servers in delegations are identified by name, rather than by IP address. This means that a resolving name server must issue another DNS request to find out the IP address of the server to which it has been referred. If the name given in the delegation is a subdomain of the domain for which the delegation is being provided, there is a <a href="/wiki/Circular_dependency" title="Circular dependency">circular dependency</a>. In this case, the name server providing the delegation must also provide one or more IP addresses for the <a href="/wiki/Authoritative_name_server" class="mw-redirect" title="Authoritative name server">authoritative name server</a> mentioned in the delegation. This information is called glue. The delegating name server provides this glue in the form of records in the additional section of the DNS response, and provides the delegation in the authority section of the response. A glue record is a combination of the name server and IP address. For example, if the <a href="/wiki/Authoritative_name_server" class="mw-redirect" title="Authoritative name server">authoritative name server</a> for example.org is ns1.example.org, a computer trying to resolve www.example.org first resolves ns1.example.org. As ns1 is contained in example.org, this requires resolving example.org first, which presents a circular dependency. To break the dependency, the name server for the <a href="/wiki/Top_level_domain" class="mw-redirect" title="Top level domain">top level domain</a> org includes glue along with the delegation for example.org. The glue records are address records that provide IP addresses for ns1.example.org. The resolver uses one or more of these IP addresses to query one of the domain's authoritative servers, which allows it to complete the DNS query. <div class="mw-heading mw-heading3"><h3 id="Record_caching">Record caching</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=13" title="Edit section: Record caching">edit</a>]</div> A common approach to reduce the burden on DNS servers is to cache the results of name resolution locally or on intermediary resolver hosts. Each DNS query result comes with a time to live (TTL), which indicates how long the information remains valid before it needs to be discarded or refreshed. This TTL is determined by the administrator of the authoritative DNS server and can range from a few seconds to several days or even weeks.<a href="#cite_note-33">[33]</a> As a result of this distributed caching architecture, changes to DNS records do not propagate throughout the network immediately, but require all caches to expire and to be refreshed after the TTL. RFC 1912 conveys basic rules for determining appropriate TTL values. Some resolvers may override TTL values, as the protocol supports caching for up to sixty-eight years or no caching at all. <a href="/wiki/Negative_cache" title="Negative cache">Negative caching</a>, i.e. the caching of the fact of non-existence of a record, is determined by name servers authoritative for a zone which must include the <a href="/wiki/SOA_record" title="SOA record">Start of Authority</a> (SOA) record when reporting no data of the requested type exists. The value of the minimum field of the SOA record and the TTL of the SOA itself is used to establish the TTL for the negative answer. <div class="mw-heading mw-heading3"><h3 id="Reverse_lookup">Reverse lookup</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=14" title="Edit section: Reverse lookup">edit</a>]</div> A <a href="/wiki/Reverse_DNS_lookup" title="Reverse DNS lookup">reverse DNS lookup</a> is a query of the DNS for domain names when the IP address is known. Multiple domain names may be associated with an IP address. The DNS stores IP addresses in the form of domain names as specially formatted names in pointer (PTR) records within the infrastructure top-level domain <a href="/wiki/.arpa" title=".arpa">arpa</a>. For IPv4, the domain is in-addr.arpa. For IPv6, the reverse lookup domain is ip6.arpa. The IP address is represented as a name in reverse-ordered octet representation for IPv4, and reverse-ordered nibble representation for IPv6. When performing a reverse lookup, the DNS client converts the address into these formats before querying the name for a PTR record following the delegation chain as for any DNS query. For example, assuming the IPv4 address 208.80.152.2 is assigned to Wikimedia, it is represented as a DNS name in reverse order: 2.152.80.208.in-addr.arpa. When the DNS resolver gets a pointer (PTR) request, it begins by querying the root servers, which point to the servers of <a href="/wiki/American_Registry_for_Internet_Numbers" title="American Registry for Internet Numbers">American Registry for Internet Numbers</a> (ARIN) for the 208.in-addr.arpa zone. ARIN's servers delegate 152.80.208.in-addr.arpa to Wikimedia to which the resolver sends another query for 2.152.80.208.in-addr.arpa, which results in an authoritative response. <div class="mw-heading mw-heading3"><h3 id="Client_lookup">Client lookup</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=15" title="Edit section: Client lookup">edit</a>]</div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:DNS_Architecture.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/60/DNS_Architecture.svg/400px-DNS_Architecture.svg.png" decoding="async" width="400" height="146" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/60/DNS_Architecture.svg/600px-DNS_Architecture.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/60/DNS_Architecture.svg/800px-DNS_Architecture.svg.png 2x" data-file-width="512" data-file-height="187" /></a><figcaption>DNS resolution sequence</figcaption></figure> Users generally do not communicate directly with a DNS resolver. Instead DNS resolution takes place transparently in applications such as <a href="/wiki/Web_browser" title="Web browser">web browsers</a>, <a href="/wiki/E-mail_client" class="mw-redirect" title="E-mail client">e-mail clients</a>, and other Internet applications. When an application makes a request that requires a domain name lookup, such programs send a resolution request to the <a href="/wiki/DNS_resolver" class="mw-redirect" title="DNS resolver">DNS resolver</a> in the local operating system, which in turn handles the communications required. The DNS resolver will almost invariably have a cache (see above) containing recent lookups. If the cache can provide the answer to the request, the resolver will return the value in the cache to the program that made the request. If the cache does not contain the answer, the resolver will send the request to one or more designated DNS servers. In the case of most home users, the Internet service provider to which the machine connects will usually supply this DNS server: such a user will either have configured that server's address manually or allowed <a href="/wiki/Dynamic_Host_Configuration_Protocol" title="Dynamic Host Configuration Protocol">DHCP</a> to set it; however, where systems administrators have configured systems to use their own DNS servers, their DNS resolvers point to separately maintained name servers of the organization. In any event, the name server thus queried will follow the process outlined <a href="#Address_resolution_mechanism">above</a>, until it either successfully finds a result or does not. It then returns its results to the DNS resolver; assuming it has found a result, the resolver duly caches that result for future use, and hands the result back to the software which initiated the request. <div class="mw-heading mw-heading4"><h4 id="Broken_resolvers">Broken resolvers</h4>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=16" title="Edit section: Broken resolvers">edit</a>]</div> Some large ISPs have configured their DNS servers to violate rules, such as by disobeying TTLs, or by indicating that a domain name does not exist just because one of its name servers does not respond.<a href="#cite_note-34">[34]</a> Some applications such as web browsers maintain an internal DNS cache to avoid repeated lookups via the network. This practice can add extra difficulty when debugging DNS issues as it obscures the history of such data. These caches typically use very short caching times on the order of one minute.<a href="#cite_note-35">[35]</a> <a href="/wiki/Internet_Explorer" title="Internet Explorer">Internet Explorer</a> represents a notable exception: versions up to IE 3.x cache DNS records for 24 hours by default. Internet Explorer 4.x and later versions (up to IE 8) decrease the default timeout value to half an hour, which may be changed by modifying the default configuration.<a href="#cite_note-36">[36]</a> When <a href="/wiki/Google_Chrome" title="Google Chrome">Google Chrome</a> detects issues with the DNS server it displays a specific error message. <div class="mw-heading mw-heading3"><h3 id="Other_applications">Other applications</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=17" title="Edit section: Other applications">edit</a>]</div> The Domain Name System includes several other functions and features. Hostnames and IP addresses are not required to match in a one-to-one relationship. Multiple hostnames may correspond to a single IP address, which is useful in <a href="/wiki/Virtual_hosting" title="Virtual hosting">virtual hosting</a>, in which many web sites are served from a single host. Alternatively, a single hostname may resolve to many IP addresses to facilitate <a href="/wiki/Fault_tolerance" title="Fault tolerance">fault tolerance</a> and <a href="/wiki/Load_balancing_(computing)" title="Load balancing (computing)">load distribution</a> to multiple server instances across an enterprise or the global Internet. DNS serves other purposes in addition to translating names to IP addresses. For instance, <a href="/wiki/Mail_transfer_agent" class="mw-redirect" title="Mail transfer agent">mail transfer agents</a> use DNS to find the best mail server to deliver <a href="/wiki/E-mail" class="mw-redirect" title="E-mail">e-mail</a>: An <a href="/wiki/MX_record" title="MX record">MX record</a> provides a mapping between a domain and a mail exchanger; this can provide an additional layer of fault tolerance and load distribution. The DNS is used for efficient storage and distribution of IP addresses of blacklisted email hosts. A common method is to place the IP address of the subject host into the sub-domain of a higher level domain name, and to resolve that name to a record that indicates a positive or a negative indication. For example: <ul><li>The address 203.0.113.5 is blacklisted. It points to <style data-mw-deduplicate="TemplateStyles:r886049734">.mw-parser-output .monospaced{font-family:monospace,monospace}</style>5.113.0.203.blacklist.example, which resolves to 127.0.0.1.</li> <li>The address 203.0.113.6 is not blacklisted and points to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">6.113.0.203.blacklist.example. This hostname is either not configured, or resolves to 127.0.0.2.</li></ul> E-mail servers can query blacklist.example to find out if a specific host connecting to them is in the blacklist. Many of such blacklists, either subscription-based or free of cost, are available for use by email administrators and anti-spam software. To provide resilience in the event of computer or network failure, multiple DNS servers are usually provided for coverage of each domain. At the top level of global DNS, thirteen groups of <a href="/wiki/Root_name_server" title="Root name server">root name servers</a> exist, with additional "copies" of them distributed worldwide via <a href="/wiki/Anycast" title="Anycast">anycast</a> addressing. <a href="/wiki/Dynamic_DNS" title="Dynamic DNS">Dynamic DNS</a> (DDNS) updates a DNS server with a client IP address on-the-fly, for example, when moving between ISPs or mobile <a href="/wiki/Hotspot_(Wi-Fi)" class="mw-redirect" title="Hotspot (Wi-Fi)">hot spots</a>, or when the IP address changes administratively. <div class="mw-heading mw-heading2"><h2 id="DNS_message_format">DNS message format</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=18" title="Edit section: DNS message format">edit</a>]</div> The DNS protocol uses two types of DNS messages, queries and responses; both have the same format. Each message consists of a header and four sections: question, answer, authority, and an additional space. A header field (flags) controls the content of these four sections.<a href="#cite_note-rfc1034-22">[22]</a> The header section consists of the following fields: Identification, Flags, Number of questions, Number of answers, Number of authority resource records (RRs), and Number of additional RRs. Each field is 16 bits long, and appears in the order given. The identification field is used to match responses with queries. The flag field consists of sub-fields as follows: <table class="wikitable" style="margin: 1em auto 1em auto"> <caption>Header flags format </caption> <tbody><tr> <th>Field</th> <th>Description</th> <th>Length (<a href="/wiki/Bit" title="Bit">bits</a>) </th></tr> <tr> <td>QR</td> <td>Indicates if the message is a query (0) or a reply (1)</td> <td>1 </td></tr> <tr> <td>OPCODE</td> <td>The type can be QUERY (standard query, 0), IQUERY (inverse query, 1), or STATUS (server status request, 2)</td> <td>4 </td></tr> <tr> <td>AA</td> <td>Authoritative Answer, in a response, indicates if the DNS server is authoritative for the queried hostname</td> <td>1 </td></tr> <tr> <td>TC</td> <td>TrunCation, indicates that this message was truncated due to excessive length</td> <td>1 </td></tr> <tr> <td>RD</td> <td>Recursion Desired, indicates if the client means a recursive query</td> <td>1 </td></tr> <tr> <td>RA</td> <td>Recursion Available, in a response, indicates if the replying DNS server supports recursion</td> <td>1 </td></tr> <tr> <td>Z</td> <td>Zero, reserved for future use</td> <td>3 </td></tr> <tr> <td>RCODE</td> <td>Response code, can be NOERROR (0), FORMERR (1, Format error), SERVFAIL (2), NXDOMAIN (3, Nonexistent domain), etc.<a href="#cite_note-37">[37]</a></td> <td>4 </td></tr></tbody></table> After the flags word, the header ends with four 16-bit integers which contain the number of records in each of the sections that follow, in the same order. <table class="wikitable" style="margin: 0 auto; text-align:center"> <caption>DNS Header </caption> <tbody><tr> <th colspan="2">Offsets </th> <th colspan="8" style="border-left:1px; text-align:left;">0 </th> <th colspan="8" style="border-left:1px; text-align:left;">1 </th> <th colspan="8" style="border-left:1px; text-align:left;">2 </th> <th colspan="8" style="border-left:1px; text-align:left;">3 </th></tr> <tr> <th><a href="/wiki/Octet_(computing)" title="Octet (computing)">Octet</a></th> <th><a href="/wiki/Bit" title="Bit">Bit</a> </th> <th style="text-align:left;">0</th> <th>1</th> <th>2</th> <th>3</th> <th>4</th> <th>5</th> <th>6</th> <th>7</th> <th>0</th> <th>1 </th> <th style="text-align:left;">2</th> <th>3</th> <th>4</th> <th>5</th> <th>6</th> <th>7</th> <th>0</th> <th>1</th> <th>2</th> <th>3 </th> <th style="text-align:left;">4</th> <th>5</th> <th>6</th> <th>7</th> <th>0</th> <th>1</th> <th>2</th> <th>3</th> <th>4</th> <th>5 </th> <th style="text-align:left;">6</th> <th>7 </th></tr> <tr> <th rowspan="2">0 </th> <th rowspan="2">0 </th> <td rowspan="2" colspan="16">Transaction ID</td> <td colspan="16">Flags </td></tr> <tr> <td><style data-mw-deduplicate="TemplateStyles:r1231500821">@supports(writing-mode:vertical-lr){.mw-parser-output .ts-vertical-text{letter-spacing:-0.12em;line-height:1em;text-orientation:upright;writing-mode:vertical-lr;width:1em}}</style>QR </td> <td colspan="4">OPCODE </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1231500821">AA </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1231500821">TC </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1231500821">RD </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1231500821">RA </td> <td colspan="3">Z </td> <td colspan="4">RCODE </td></tr> <tr> <th>4 </th> <th>32 </th> <td colspan="16">Number of questions </td> <td colspan="16">Number of answers </td></tr> <tr> <th>8 </th> <th>64 </th> <td colspan="16">Number of authority RRs </td> <td colspan="16">Number of additional RRs </td></tr> </tbody></table> <div class="mw-heading mw-heading3"><h3 id="Question_section">Question section</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=19" title="Edit section: Question section">edit</a>]</div> The question section has a simpler format than the resource record format used in the other sections. Each question record (there is usually just one in the section) contains the following fields: <table class="wikitable" style="margin: 1em auto 1em auto"> <caption>Resource record (RR) fields </caption> <tbody><tr> <th>Field</th> <th>Description</th> <th>Length (<a href="/wiki/Octet_(computing)" title="Octet (computing)">octets</a>) </th></tr> <tr> <td>NAME</td> <td>Name of the requested resource</td> <td>Variable </td></tr> <tr> <td>TYPE</td> <td>Type of RR (A, AAAA, MX, TXT, etc.)</td> <td>2 </td></tr> <tr> <td>CLASS</td> <td>Class code</td> <td>2 </td></tr></tbody></table> The domain name is broken into discrete labels which are concatenated; each label is prefixed by the length of that label.<a href="#cite_note-38">[38]</a> <div class="mw-heading mw-heading2"><h2 id="Resource_records">Resource records</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=20" title="Edit section: Resource records">edit</a>]</div> The Domain Name System specifies a database of information elements for network resources. The types of information elements are categorized and organized with a <a href="/wiki/List_of_DNS_record_types" title="List of DNS record types">list of DNS record types</a>, the resource records (RRs). Each record has a type (name and number), an expiration time (<a href="/wiki/Time_to_live#DNS_records" title="Time to live">time to live</a>), a class, and type-specific data. Resource records of the same type are described as a resource record set (RRset), having no special ordering. DNS resolvers return the entire set upon query, but servers may implement <a href="/wiki/Round-robin_DNS" title="Round-robin DNS">round-robin ordering</a> to achieve <a href="/wiki/Load_balancing_(computing)" title="Load balancing (computing)">load balancing</a>. In contrast, the <a href="/wiki/Domain_Name_System_Security_Extensions" title="Domain Name System Security Extensions">Domain Name System Security Extensions</a> (DNSSEC) work on the complete set of resource record in canonical order. When sent over an <a href="/wiki/Internet_Protocol" title="Internet Protocol">Internet Protocol</a> network, all records (answer, authority, and additional sections) use the common format specified in RFC 1035:<a href="#cite_note-39">[39]</a> <table class="wikitable" style="margin: 1em auto 1em auto"> <caption>Resource record (RR) fields </caption> <tbody><tr> <th>Field</th> <th>Description</th> <th>Length (<a href="/wiki/Octet_(computing)" title="Octet (computing)">octets</a>) </th></tr> <tr> <td>NAME</td> <td>Name of the node to which this record pertains</td> <td>Variable </td></tr> <tr> <td>TYPE</td> <td>Type of RR in numeric form (e.g., 15 for MX RRs)</td> <td>2 </td></tr> <tr> <td>CLASS</td> <td>Class code</td> <td>2 </td></tr> <tr> <td><a href="/wiki/Time_to_live" title="Time to live">TTL</a></td> <td>Count of seconds that the RR stays valid (The maximum is 231−1, which is about 68 years)</td> <td>4 </td></tr> <tr> <td>RDLENGTH</td> <td>Length of RDATA field (specified in octets)</td> <td>2 </td></tr> <tr> <td>RDATA</td> <td>Additional RR-specific data</td> <td>Variable, as per RDLENGTH </td></tr></tbody></table> NAME is the fully qualified domain name of the node in the tree.[<a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify">clarification needed</a>] On the wire, the name may be shortened using label compression where ends of domain names mentioned earlier in the packet can be substituted for the end of the current domain name. TYPE is the record type. It indicates the format of the data and it gives a hint of its intended use. For example, the A record is used to translate from a domain name to an <a href="/wiki/IPv4_address" class="mw-redirect" title="IPv4 address">IPv4 address</a>, the NS record lists which name servers can answer lookups on a <a href="/wiki/DNS_zone" title="DNS zone">DNS zone</a>, and the MX record specifies the mail server used to handle mail for a domain specified in an e-mail address. RDATA is data of type-specific relevance, such as the IP address for address records, or the priority and hostname for MX records. Well known record types may use label compression in the RDATA field, but "unknown" record types must not (RFC 3597). The CLASS of a record is set to IN (for Internet) for common DNS records involving Internet hostnames, servers, or IP addresses. In addition, the classes <a href="/wiki/Chaosnet" title="Chaosnet">Chaos</a> (CH) and <a href="/wiki/Hesiod_(name_service)" title="Hesiod (name service)">Hesiod</a> (HS) exist.<a href="#cite_note-40">[40]</a> Each class is an independent name space with potentially different delegations of DNS zones. In addition to resource records defined in a <a href="/wiki/Zone_file" title="Zone file">zone file</a>, the domain name system also defines several request types that are used only in communication with other DNS nodes (on the wire), such as when performing zone transfers (AXFR/IXFR) or for <a href="/wiki/Extension_Mechanisms_for_DNS" title="Extension Mechanisms for DNS">EDNS</a> (OPT). <div class="mw-heading mw-heading3"><h3 id="Wildcard_records">Wildcard records</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=21" title="Edit section: Wildcard records">edit</a>]</div> The domain name system supports <a href="/wiki/Wildcard_DNS_record" title="Wildcard DNS record">wildcard DNS records</a> which specify names that start with the asterisk label, <code>*</code>, e.g., <code>*.example</code>.<a href="#cite_note-rfc1034-22">[22]</a><a href="#cite_note-rfc4592-41">[41]</a> DNS records belonging to wildcard domain names specify rules for generating resource records within a single DNS zone by substituting whole labels with matching components of the query name, including any specified descendants. For example, in the following configuration, the DNS zone x.example specifies that all subdomains, including subdomains of subdomains, of x.example use the mail exchanger (MX) a.x.example. The A record for a.x.example is needed to specify the mail exchanger IP address. As this has the result of excluding this domain name and its subdomains from the wildcard matches, an additional MX record for the subdomain a.x.example, as well as a wildcarded MX record for all of its subdomains, must also be defined in the DNS zone. <div class="mw-highlight mw-highlight-lang-zone mw-content-ltr" dir="ltr"><pre>x.example. MX 10 a.x.example. *.x.example. MX 10 a.x.example. *.a.x.example. MX 10 a.x.example. a.x.example. MX 10 a.x.example. a.x.example. AAAA 2001:db8::1 </pre></div> The role of wildcard records was refined in <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4592">4592</a>, because the original definition in <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">1034</a> was incomplete and resulted in misinterpretations by implementers.<a href="#cite_note-rfc4592-41">[41]</a> <div class="mw-heading mw-heading2"><h2 id="Protocol_extensions">Protocol extensions</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=22" title="Edit section: Protocol extensions">edit</a>]</div> The original DNS protocol had limited provisions for extension with new features. In 1999, Paul Vixie published in RFC 2671 (superseded by RFC 6891) an extension mechanism, called <a href="/wiki/Extension_Mechanisms_for_DNS" title="Extension Mechanisms for DNS">Extension Mechanisms for DNS</a> (EDNS) that introduced optional protocol elements without increasing overhead when not in use. This was accomplished through the OPT pseudo-resource record that only exists in wire transmissions of the protocol, but not in any zone files. Initial extensions were also suggested (EDNS0), such as increasing the DNS message size in UDP datagrams. <div class="mw-heading mw-heading2"><h2 id="Dynamic_zone_updates">Dynamic zone updates</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=23" title="Edit section: Dynamic zone updates">edit</a>]</div> <a href="/wiki/Dynamic_DNS" title="Dynamic DNS">Dynamic DNS updates</a> use the UPDATE DNS opcode to add or remove resource records dynamically from a zone database maintained on an authoritative DNS server.<a href="#cite_note-rfc2136-42">[42]</a> This facility is useful to register network clients into the DNS when they boot or become otherwise available on the network. As a booting client may be assigned a different IP address each time from a <a href="/wiki/DHCP" class="mw-redirect" title="DHCP">DHCP</a> server, it is not possible to provide static DNS assignments for such clients. <div class="mw-heading mw-heading2"><h2 id="Transport_protocols">Transport protocols</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=24" title="Edit section: Transport protocols">edit</a>]</div> From the time of its origin in 1983 the DNS has used the <a href="/wiki/User_Datagram_Protocol" title="User Datagram Protocol">User Datagram Protocol</a> (UDP) for transport over IP. Its limitations have motivated numerous protocol developments for reliability, security, privacy, and other criteria, in the following decades. <div class="mw-heading mw-heading3"><h3 id="DNS_over_UDP/TCP/53_(Do53)">DNS over UDP/TCP/53 (Do53)</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=25" title="Edit section: DNS over UDP/TCP/53 (Do53)">edit</a>]</div> UDP reserves <a href="/wiki/Port_number" class="mw-redirect" title="Port number">port number</a> 53 for servers listening to queries.<a href="#cite_note-rfc1035-5">[5]</a> Such queries consist of a clear-text request sent in a single UDP packet from the client, responded to with a clear-text reply sent in a single UDP packet from the server. When the length of the answer exceeds 512 bytes and both client and server support <a href="/wiki/Extension_Mechanisms_for_DNS" title="Extension Mechanisms for DNS">Extension Mechanisms for DNS</a> (EDNS), larger UDP packets may be used.<a href="#cite_note-43">[43]</a> Use of DNS over UDP is limited by, among other things, its lack of transport-layer encryption, authentication, reliable delivery, and message length. In 1989, RFC 1123 specified optional <a href="/wiki/Transmission_Control_Protocol" title="Transmission Control Protocol">Transmission Control Protocol</a> (TCP) transport for DNS queries, replies and, particularly, <a href="/wiki/DNS_zone_transfer" title="DNS zone transfer">zone transfers</a>. Via fragmentation of long replies, TCP allows longer responses, reliable delivery, and re-use of long-lived connections between clients and servers. For larger responses, the server refers the client to TCP transport. <div class="mw-heading mw-heading3"><h3 id="DNS_over_TLS_(DoT)">DNS over TLS (DoT)</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=26" title="Edit section: DNS over TLS (DoT)">edit</a>]</div> <a href="/wiki/DNS_over_TLS" title="DNS over TLS">DNS over TLS</a> emerged as an IETF standard for encrypted DNS in 2016, utilizing Transport Layer Security (TLS) to protect the entire connection, rather than just the DNS payload. DoT servers listen on TCP port 853. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7858">7858</a> specifies that opportunistic encryption and authenticated encryption may be supported, but did not make either server or client authentication mandatory. <div class="mw-heading mw-heading3"><h3 id="DNS_over_HTTPS_(DoH)">DNS over HTTPS (DoH)</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=27" title="Edit section: DNS over HTTPS (DoH)">edit</a>]</div> <a href="/wiki/DNS_over_HTTPS" title="DNS over HTTPS">DNS over HTTPS</a> was developed as a competing standard for DNS query transport in 2018, tunneling DNS query data over HTTPS, which transports HTTP over TLS. DoH was promoted as a more web-friendly alternative to DNS since, like DNSCrypt, it uses TCP port 443, and thus looks similar to web traffic, though they are easily differentiable in practice without proper padding.<a href="#cite_note-44">[44]</a> <div class="mw-heading mw-heading3"><h3 id="DNS_over_QUIC_(DoQ)">DNS over QUIC (DoQ)</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=28" title="Edit section: DNS over QUIC (DoQ)">edit</a>]</div> RFC 9250, published in 2022 by the <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">Internet Engineering Task Force</a>, describes DNS over <a href="/wiki/QUIC" title="QUIC">QUIC</a>. It has "privacy properties similar to DNS over TLS (DoT) [...], and latency characteristics similar to classic DNS over UDP". This method is not the same as DNS over <a href="/wiki/HTTP/3" title="HTTP/3">HTTP/3</a>.<a href="#cite_note-45">[45]</a> <div class="mw-heading mw-heading3"><h3 id="Oblivious_DoH_(ODoH)_and_predecessor_Oblivious_DNS_(ODNS)">Oblivious DoH (ODoH) and predecessor Oblivious DNS (ODNS)</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=29" title="Edit section: Oblivious DoH (ODoH) and predecessor Oblivious DNS (ODNS)">edit</a>]</div> Oblivious DNS (ODNS) was invented and implemented by researchers at <a href="/wiki/Princeton_University" title="Princeton University">Princeton University</a> and the <a href="/wiki/University_of_Chicago" title="University of Chicago">University of Chicago</a> as an extension to unencrypted DNS,<a href="#cite_note-46">[46]</a> before DoH was standardized and widely deployed. Apple and Cloudflare subsequently deployed the technology in the context of DoH, as Oblivious DoH (ODoH).<a href="#cite_note-47">[47]</a> ODoH combines ingress/egress separation (invented in ODNS) with DoH's HTTPS tunneling and TLS transport-layer encryption in a single protocol.<a href="#cite_note-48">[48]</a> <div class="mw-heading mw-heading3"><h3 id="DNS_over_Tor">DNS over Tor</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=30" title="Edit section: DNS over Tor">edit</a>]</div> DNS may be run over <a href="/wiki/Virtual_private_network" title="Virtual private network">virtual private networks</a> (VPNs) and <a href="/wiki/Tunneling_protocol" title="Tunneling protocol">tunneling protocols</a>. A use which has become common since 2019 to warrant its own frequently used acronym is DNS over <a href="/wiki/Tor_(network)" title="Tor (network)">Tor</a>. The privacy gains of Oblivious DNS can be garnered through the use of the preexisting Tor network of ingress and egress nodes, paired with the transport-layer encryption provided by TLS.<a href="#cite_note-49">[49]</a> <div class="mw-heading mw-heading3"><h3 id="DNSCrypt">DNSCrypt</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=31" title="Edit section: DNSCrypt">edit</a>]</div> The <a href="/wiki/DNSCrypt" title="DNSCrypt">DNSCrypt</a> protocol, which was developed in 2011 outside the <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a> standards framework, introduced DNS encryption on the downstream side of recursive resolvers, wherein clients encrypt query payloads using servers' public keys, which are published in the DNS (rather than relying upon third-party certificate authorities) and which may in turn be protected by DNSSEC signatures.<a href="#cite_note-50">[50]</a> DNSCrypt uses either TCP or UDP port 443, the same port as HTTPS encrypted web traffic. This introduced not only privacy regarding the content of the query, but also a significant measure of firewall-traversal capability. In 2019, DNSCrypt was further extended to support an "anonymized" mode, similar to the proposed "Oblivious DNS", in which an ingress node receives a query which has been encrypted with the public key of a different server, and relays it to that server, which acts as an egress node, performing the recursive resolution.<a href="#cite_note-Anonymized_DNSCrypt_specification-51">[51]</a> Privacy of user/query pairs is created, since the ingress node does not know the content of the query, while the egress nodes does not know the identity of the client. DNSCrypt was first implemented in production by <a href="/wiki/OpenDNS" title="OpenDNS">OpenDNS</a> in December 2011. There are several free and open source software implementations that additionally integrate ODoH.<a href="#cite_note-ODoH_(2022)-52">[52]</a> It is available for a variety of operating systems, including Unix, Apple iOS, Linux, Android, and Windows. <div class="mw-heading mw-heading2"><h2 id="Security_issues">Security issues</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=32" title="Edit section: Security issues">edit</a>]</div> Originally, security concerns were not major design considerations for DNS software or any software for deployment on the early Internet, as the network was not open for participation by the general public. However, the expansion of the Internet into the commercial sector in the 1990s changed the requirements for security measures to protect <a href="/wiki/Data_integrity" title="Data integrity">data integrity</a> and user <a href="/wiki/Authentication" title="Authentication">authentication</a>. Several vulnerability issues were discovered and exploited by malicious users. One such issue is <a href="/wiki/DNS_cache_poisoning" class="mw-redirect" title="DNS cache poisoning">DNS cache poisoning</a>, in which data is distributed to caching resolvers under the pretense of being an authoritative origin server, thereby polluting the data store with potentially false information and long expiration times (time-to-live). Subsequently, legitimate application requests may be redirected to network hosts operated with malicious intent. DNS responses traditionally do not have a <a href="/wiki/Cryptographic_signature" class="mw-redirect" title="Cryptographic signature">cryptographic signature</a>, leading to many attack possibilities; the <a href="/wiki/Domain_Name_System_Security_Extensions" title="Domain Name System Security Extensions">Domain Name System Security Extensions</a> (DNSSEC) modify DNS to add support for cryptographically signed responses.<a href="#cite_note-53">[53]</a> <a href="/wiki/DNSCurve" title="DNSCurve">DNSCurve</a> has been proposed as an alternative to DNSSEC. Other extensions, such as <a href="/wiki/TSIG" title="TSIG">TSIG</a>, add support for cryptographic authentication between trusted peers and are commonly used to authorize zone transfer or dynamic update operations. Some domain names may be used to achieve spoofing effects. For example, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">paypal.com and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">paypa1.com are different names, yet users may be unable to distinguish them in a graphical user interface depending on the user's chosen <a href="/wiki/Typeface" title="Typeface">typeface</a>. In many fonts the letter l and the numeral 1 look very similar or even identical. This problem, known as the <a href="/wiki/IDN_homograph_attack" title="IDN homograph attack">IDN homograph attack</a>, is acute in systems that support <a href="/wiki/Internationalized_domain_name" title="Internationalized domain name">internationalized domain names</a>, as many character codes in <a href="/wiki/ISO_10646" class="mw-redirect" title="ISO 10646">ISO 10646</a> may appear identical on typical computer screens. This vulnerability is occasionally exploited in <a href="/wiki/Phishing" title="Phishing">phishing</a>.<a href="#cite_note-54">[54]</a> Techniques such as <a href="/wiki/Forward-confirmed_reverse_DNS" title="Forward-confirmed reverse DNS">forward-confirmed reverse DNS</a> can also be used to help validate DNS results. DNS can also "leak" from otherwise secure or private connections, if attention is not paid to their configuration, and at times DNS has been used to bypass firewalls by malicious persons, and <a href="/wiki/Data_exfiltration" title="Data exfiltration">exfiltrate</a> data, since it is often seen as innocuous. <div class="mw-heading mw-heading2"><h2 id="Privacy_and_tracking_issues">Privacy and tracking issues</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=33" title="Edit section: Privacy and tracking issues">edit</a>]</div> Originally designed as a public, hierarchical, distributed and heavily cached database, DNS protocol has no confidentiality controls. User queries and nameserver responses are being sent unencrypted which enables <a href="/wiki/Sniffing_attack" title="Sniffing attack">network packet sniffing</a>, <a href="/wiki/DNS_hijacking" title="DNS hijacking">DNS hijacking</a>, <a href="/wiki/DNS_spoofing" title="DNS spoofing">DNS cache poisoning</a> and <a href="/wiki/Man-in-the-middle_attack" title="Man-in-the-middle attack">man-in-the-middle attacks</a>. This deficiency is commonly used by cybercriminals and network operators for marketing purposes, user authentication on <a href="/wiki/Captive_portal" title="Captive portal">captive portals</a> and <a href="/wiki/Internet_censorship" title="Internet censorship">censorship</a>.<a href="#cite_note-Huston-2019-55">[55]</a> User privacy is further exposed by proposals for increasing the level of client IP information in DNS queries (RFC 7871) for the benefit of <a href="/wiki/Content_delivery_network" title="Content delivery network">Content Delivery Networks</a>. The main approaches that are in use to counter privacy issues with DNS: <ul><li><a href="/wiki/VPN" class="mw-redirect" title="VPN">VPNs</a>, which move DNS resolution to the VPN operator and hide user traffic from local ISP,</li> <li><a href="/wiki/Tor_(network)" title="Tor (network)">Tor</a>, which replaces traditional DNS resolution with anonymous <a href="/wiki/.onion" title=".onion">.onion</a> domains, hiding both name resolution and user traffic behind <a href="/wiki/Onion_routing" title="Onion routing">onion routing</a> counter-surveillance,</li> <li><a href="/wiki/Proxy_server" title="Proxy server">Proxies</a> and public DNS servers, which move the actual DNS resolution to a third-party provider, who usually promises little or no request logging and optional added features, such as DNS-level <a href="/wiki/Ad_blocking" title="Ad blocking">advertisement</a> or pornography blocking. <ul><li>Public DNS servers can be queried using traditional DNS protocol, in which case they provide no protection from local surveillance, or <a href="/wiki/DNS_over_HTTPS" title="DNS over HTTPS">DNS over HTTPS</a>, <a href="/wiki/DNS_over_TLS" title="DNS over TLS">DNS over TLS</a> and <a href="/wiki/DNSCrypt" title="DNSCrypt">DNSCrypt</a>, which do provide such protection</li></ul></li></ul> Solutions preventing DNS inspection by local network operator are criticized for thwarting corporate network security policies and Internet censorship. They are also criticized from a privacy point of view, as giving away the DNS resolution to the hands of a small number of companies known for monetizing user traffic and for centralizing DNS name resolution, which is generally perceived as harmful for the Internet.<a href="#cite_note-Huston-2019-55">[55]</a> <style data-mw-deduplicate="TemplateStyles:r1244412712">.mw-parser-output .templatequote{overflow:hidden;margin:1em 0;padding:0 32px}.mw-parser-output .templatequotecite{line-height:1.5em;text-align:left;margin-top:0}@media(min-width:500px){.mw-parser-output .templatequotecite{padding-left:1.6em}}</style><blockquote class="templatequote">Google is the dominant provider of the platform in <a href="/wiki/Android_(operating_system)" title="Android (operating system)">Android</a>, the browser in Chrome, and the DNS resolver in the 8.8.8.8 service. Would this scenario be a case of a single corporate entity being in a position of overarching control of the entire namespace of the Internet? <a href="/wiki/Netflix" title="Netflix">Netflix</a> already fielded an app that used its own DNS resolution mechanism independent of the platform upon which the app was running. What if the <a href="/wiki/Facebook" title="Facebook">Facebook</a> app included DoH? What if <a href="/wiki/Apple_Inc." title="Apple Inc.">Apple</a>'s <a href="/wiki/IOS" title="IOS">iOS</a> used a DoH-resolution mechanism to bypass local DNS resolution and steer all DNS queries from Apple's platforms to a set of Apple-operated name resolvers?<div class="templatequotecite">— <cite>DNS Privacy and the IETF</cite></div></blockquote> <div class="mw-heading mw-heading2"><h2 id="Domain_name_registration">Domain name registration</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=34" title="Edit section: Domain name registration">edit</a>]</div> The right to use a domain name is delegated by domain name registrars which are accredited by the <a href="/wiki/Internet_Corporation_for_Assigned_Names_and_Numbers" class="mw-redirect" title="Internet Corporation for Assigned Names and Numbers">Internet Corporation for Assigned Names and Numbers</a> (ICANN) or other organizations such as <a href="/wiki/OpenNIC" title="OpenNIC">OpenNIC</a>, that are charged with overseeing the name and number systems of the Internet. In addition to ICANN, each top-level domain (TLD) is maintained and serviced technically by an administrative organization, operating a registry. A registry is responsible for operating the database of names within its authoritative zone, although the term is most often used for TLDs. A registrant is a person or organization who asked for domain registration.<a href="#cite_note-rfc7719-23">[23]</a> The registry receives registration information from each domain name registrar, which is authorized (accredited) to assign names in the corresponding zone and publishes the information using the <a href="/wiki/WHOIS" title="WHOIS">WHOIS</a> protocol. As of 2015, usage of <a href="/wiki/Registration_Data_Access_Protocol" title="Registration Data Access Protocol">RDAP</a> is being considered.<a href="#cite_note-56">[56]</a> ICANN publishes the complete list of TLDs, TLD registries, and domain name registrars. Registrant information associated with domain names is maintained in an online database accessible with the WHOIS service. For most of the more than 290 <a href="/wiki/Country_code_top-level_domain" title="Country code top-level domain">country code top-level domains</a> (ccTLDs), the domain registries maintain the WHOIS (Registrant, name servers, expiration dates, etc.) information. For instance, <a href="/wiki/DENIC" title="DENIC">DENIC</a>, Germany NIC, holds the DE domain data. From about 2001, most <a href="/wiki/Generic_top-level_domain" title="Generic top-level domain">Generic top-level domain</a> (gTLD) registries have adopted this so-called thick registry approach, i.e. keeping the WHOIS data in central registries instead of registrar databases. For top-level domains on COM and NET, a thin registry model is used. The domain registry (e.g., <a href="/wiki/GoDaddy" title="GoDaddy">GoDaddy</a>, <a href="/wiki/Directi" class="mw-redirect" title="Directi">BigRock and PDR</a>, <a href="/wiki/VeriSign" class="mw-redirect" title="VeriSign">VeriSign</a>, etc., etc.) holds basic WHOIS data (i.e., registrar and name servers, etc.). Organizations, or registrants using ORG on the other hand, are on the <a href="/wiki/Public_Interest_Registry" title="Public Interest Registry">Public Interest Registry</a> exclusively. Some domain name registries, often called network information centers (NIC), also function as registrars to end-users, in addition to providing access to the WHOIS datasets. The top-level domain registries, such as for the domains COM, NET, and ORG use a registry-registrar model consisting of many domain name registrars.<a href="#cite_note-57">[57]</a> In this method of management, the registry only manages the domain name database and the relationship with the registrars. The registrants (users of a domain name) are customers of the registrar, in some cases through additional subcontracting of resellers. <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=35" title="Edit section: See also">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1259569809">.mw-parser-output .portalbox{padding:0;margin:0.5em 0;display:table;box-sizing:border-box;max-width:175px;list-style:none}.mw-parser-output .portalborder{border:1px solid var(--border-color-base,#a2a9b1);padding:0.1em;background:var(--background-color-neutral-subtle,#f8f9fa)}.mw-parser-output .portalbox-entry{display:table-row;font-size:85%;line-height:110%;height:1.9em;font-style:italic;font-weight:bold}.mw-parser-output .portalbox-image{display:table-cell;padding:0.2em;vertical-align:middle;text-align:center}.mw-parser-output .portalbox-link{display:table-cell;padding:0.2em 0.2em 0.2em 0.3em;vertical-align:middle}@media(min-width:720px){.mw-parser-output .portalleft{clear:left;float:left;margin:0.5em 1em 0.5em 0}.mw-parser-output .portalright{clear:right;float:right;margin:0.5em 0 0.5em 1em}}</style><ul role="navigation" aria-label="Portals" class="noprint portalbox portalborder portalright"> <li class="portalbox-entry"><a href="/wiki/File:Crystal_Clear_app_linneighborhood.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Crystal_Clear_app_linneighborhood.svg/28px-Crystal_Clear_app_linneighborhood.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Crystal_Clear_app_linneighborhood.svg/42px-Crystal_Clear_app_linneighborhood.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Crystal_Clear_app_linneighborhood.svg/56px-Crystal_Clear_app_linneighborhood.svg.png 2x" data-file-width="407" data-file-height="407" /></a><a href="/wiki/Portal:Internet" title="Portal:Internet">Internet portal</a></li></ul> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 20em;"> <ul><li><a href="/wiki/Alternative_DNS_root" title="Alternative DNS root">Alternative DNS root</a></li> <li><a href="/wiki/Comparison_of_DNS_server_software" title="Comparison of DNS server software">Comparison of DNS server software</a></li> <li><a href="/wiki/Decentralized_object_location_and_routing" title="Decentralized object location and routing">Decentralized object location and routing</a></li> <li><a href="/wiki/Domain_hijacking" title="Domain hijacking">Domain hijacking</a></li> <li><a href="/wiki/DNS_hijacking" title="DNS hijacking">DNS hijacking</a></li> <li><a href="/wiki/DNS_Long-Lived_Queries" title="DNS Long-Lived Queries">DNS Long-Lived Queries</a></li> <li><a href="/wiki/DNS_management_software" title="DNS management software">DNS management software</a></li> <li><a href="/wiki/DNS_over_HTTPS" title="DNS over HTTPS">DNS over HTTPS</a></li> <li><a href="/wiki/DNS_over_TLS" title="DNS over TLS">DNS over TLS</a></li> <li><a href="/wiki/Hierarchical_namespace" class="mw-redirect" title="Hierarchical namespace">Hierarchical namespace</a></li> <li><a href="/wiki/IPv6_brokenness_and_DNS_whitelisting" title="IPv6 brokenness and DNS whitelisting">IPv6 brokenness and DNS whitelisting</a></li> <li><a href="/wiki/Multicast_DNS" title="Multicast DNS">Multicast DNS</a></li> <li><a href="/wiki/Public_recursive_name_server" title="Public recursive name server">Public recursive name server</a></li> <li><a href="/wiki/Resolv.conf" title="Resolv.conf">resolv.conf</a></li> <li><a href="/wiki/Split-horizon_DNS" title="Split-horizon DNS">Split-horizon DNS</a></li> <li><a href="/wiki/List_of_DNS_record_types" title="List of DNS record types">List of DNS record types</a></li> <li><a href="/wiki/List_of_managed_DNS_providers" title="List of managed DNS providers">List of managed DNS providers</a></li> <li><a href="/wiki/Zone_file" title="Zone file">Zone file</a></li> <li><a href="/wiki/DNS_leak" title="DNS leak">DNS leak</a></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=36" title="Edit section: References">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-1"><a href="#cite_ref-1">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWuDangWangHe2016" 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Network Working Group. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC3467">10.17487/RFC3467</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3467">3467</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Role+of+the+Domain+Name+System+%28DNS%29&rft.pub=Network+Working+Group&rft.date=2003-02&rft_id=info%3Adoi%2F10.17487%2FRFC3467&rft.au=J.+Klensin&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc3467&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> Informational. </li> <li id="cite_note-8"><a href="#cite_ref-8">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLiuAlbitz2006" class="citation book cs1">Liu, Cricket; Albitz, Paul (2006). 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Paul Mockapetris - Internet Hall of Fame"</a>. internethalloffame.org. 23 July 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=internethalloffame.org&rft.atitle=Why+Does+the+Net+Still+Work+on+Christmas%3F+Paul+Mockapetris+-+Internet+Hall+of+Fame&rft.date=2012-07-23&rft_id=http%3A%2F%2Finternethalloffame.org%2Fblog%2F2012%2F07%2F23%2Fwhy-does-net-still-work-christmas-paul-mockapetris&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-FOOTNOTEEvans2018119-13">^ <a href="#cite_ref-FOOTNOTEEvans2018119_13-0">a</a> <a href="#cite_ref-FOOTNOTEEvans2018119_13-1">b</a> <a href="#CITEREFEvans2018">Evans 2018</a>, p. 119. </li> <li id="cite_note-FOOTNOTEEvans2018120-14"><a href="#cite_ref-FOOTNOTEEvans2018120_14-0">^</a> <a href="#CITEREFEvans2018">Evans 2018</a>, p. 120. </li> <li id="cite_note-FOOTNOTEEvans2018120–121-15"><a href="#cite_ref-FOOTNOTEEvans2018120–121_15-0">^</a> <a href="#CITEREFEvans2018">Evans 2018</a>, p. 120–121. </li> <li id="cite_note-16"><a href="#cite_ref-16">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20180914182353/https://www.internethalloffame.org/inductees/elizabeth-feinler">"Elizabeth Feinler"</a>. Internet Hall of Fame. Archived from <a rel="nofollow" class="external text" href="https://www.internethalloffame.org/inductees/elizabeth-feinler">the original</a> on 14 September 2018. Retrieved 2018-11-25.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Internet+Hall+of+Fame&rft.atitle=Elizabeth+Feinler&rft_id=https%3A%2F%2Fwww.internethalloffame.org%2Finductees%2Felizabeth-feinler&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-17"><a href="#cite_ref-17">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://internethalloffame.org/inductees/paul-mockapetris">"Paul Mockapetris | Internet Hall of Fame"</a>. internethalloffame.org. Retrieved 2020-02-12.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=internethalloffame.org&rft.atitle=Paul+Mockapetris+%7C+Internet+Hall+of+Fame&rft_id=https%3A%2F%2Finternethalloffame.org%2Finductees%2Fpaul-mockapetris&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-18"><a href="#cite_ref-18">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAndrei_Robachevsky2013" class="citation web cs1">Andrei Robachevsky (26 November 2013). <a rel="nofollow" class="external text" href="https://www.internetsociety.org/blog/2013/11/happy-30th-birthday-dns">"Happy 30th Birthday, DNS!"</a>. <a href="/wiki/Internet_Society" title="Internet Society">Internet Society</a>. Retrieved 18 December 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Happy+30th+Birthday%2C+DNS%21&rft.pub=Internet+Society&rft.date=2013-11-26&rft.au=Andrei+Robachevsky&rft_id=http%3A%2F%2Fwww.internetsociety.org%2Fblog%2F2013%2F11%2Fhappy-30th-birthday-dns&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-19"><a href="#cite_ref-19">^</a> Elizabeth Feinler, IEEE Annals, 3B2-9 man2011030074.3d 29/7/011 11:54 Page 74 </li> <li id="cite_note-Terry_USENIX_2004-20"><a href="#cite_ref-Terry_USENIX_2004_20-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTerry,_Douglas_B.1984" class="citation conference cs1">Terry, Douglas B.; et al. (June 12–15, 1984). <a rel="nofollow" class="external text" href="http://www.eecs.berkeley.edu/Pubs/TechRpts/1984/5957.html">"The Berkeley Internet Name Domain Server"</a>. Summer Conference, Salt Lake City 1984: Proceedings. USENIX Association Software Tools Users Group. pp. 23–31.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.atitle=The+Berkeley+Internet+Name+Domain+Server&rft.btitle=Summer+Conference%2C+Salt+Lake+City+1984%3A+Proceedings&rft.pages=23-31&rft.date=1984-06-12%2F1984-06-15&rft.au=Terry%2C+Douglas+B.&rft_id=http%3A%2F%2Fwww.eecs.berkeley.edu%2FPubs%2FTechRpts%2F1984%2F5957.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-BIND_Home_Page-21"><a href="#cite_ref-BIND_Home_Page_21-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFInternet_Systems_Consortium" class="citation web cs1">Internet Systems Consortium. <a rel="nofollow" class="external text" href="https://www.isc.org/bindhistory/">"The History of BIND"</a>. History of BIND. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20190630142752/https://www.isc.org/bindhistory/">Archived</a> from the original on 2019-06-30. Retrieved 4 April 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+History+of+BIND&rft.pages=History+of+BIND&rft.au=Internet+Systems+Consortium&rft_id=https%3A%2F%2Fwww.isc.org%2Fbindhistory%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-rfc1034-22">^ <a href="#cite_ref-rfc1034_22-0">a</a> <a href="#cite_ref-rfc1034_22-1">b</a> <a href="#cite_ref-rfc1034_22-2">c</a> <a href="#cite_ref-rfc1034_22-3">d</a> <a href="#cite_ref-rfc1034_22-4">e</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMockapetris1987" class="citation cs1">Mockapetris, Paul (November 1987). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">Domain Names - Domain Concepts and Facilities</a>. <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC1034">10.17487/RFC1034</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">1034</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Domain+Names+-+Domain+Concepts+and+Facilities&rft.pub=IETF&rft.date=1987-11&rft_id=info%3Adoi%2F10.17487%2FRFC1034&rft.aulast=Mockapetris&rft.aufirst=Paul&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc1034&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-rfc7719-23">^ <a href="#cite_ref-rfc7719_23-0">a</a> <a href="#cite_ref-rfc7719_23-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPaul_HoffmanAndrew_SullivanKazunori_Fujiwara2015" class="citation cs1">Paul Hoffman; Andrew Sullivan; Kazunori Fujiwara (December 2015). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7719">DNS Terminology</a>. <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC7719">10.17487/RFC7719</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7719">7719</a>. Retrieved 18 December 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=DNS+Terminology&rft.pub=IETF&rft.date=2015-12&rft_id=info%3Adoi%2F10.17487%2FRFC7719&rft.au=Paul+Hoffman&rft.au=Andrew+Sullivan&rft.au=Kazunori+Fujiwara&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc7719&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-dnsterms-24"><a href="#cite_ref-dnsterms_24-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPaul_Mockapetris1987" class="citation cs1">Paul Mockapetris (November 1987). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034#section-3.1">"Name space specifications and terminology"</a>. <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">Domain Names - Domain Concepts and Facilities</a>. <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a>. sec. 3.1. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC1034">10.17487/RFC1034</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">1034</a>. Retrieved 17 December 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Name+space+specifications+and+terminology&rft.btitle=Domain+Names+-+Domain+Concepts+and+Facilities&rft.pages=sec.-3.1&rft.pub=IETF&rft.date=1987-11&rft_id=info%3Adoi%2F10.17487%2FRFC1034&rft.au=Paul+Mockapetris&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc1034%26%23035%3Bsection-3.1&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-dnsparts-25">^ <a href="#cite_ref-dnsparts_25-0">a</a> <a href="#cite_ref-dnsparts_25-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPaul_Mockapetris1987" class="citation cs1">Paul Mockapetris (November 1987). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034#section-4.2">"How the database is divided into zones"</a>. <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">Domain Names - Domain Concepts and Facilities</a>. <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a>. sec. 4.2. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC1034">10.17487/RFC1034</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">1034</a>. Retrieved 17 December 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=How+the+database+is+divided+into+zones&rft.btitle=Domain+Names+-+Domain+Concepts+and+Facilities&rft.pages=sec.-4.2&rft.pub=IETF&rft.date=1987-11&rft_id=info%3Adoi%2F10.17487%2FRFC1034&rft.au=Paul+Mockapetris&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc1034%26%23035%3Bsection-4.2&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-26"><a href="#cite_ref-26">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLindsay2007" class="citation book cs1">Lindsay, David (2007). International Domain Name Law: ICANN and the UDRP. Bloomsbury Publishing. p. 8. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-84113-584-7" title="Special:BookSources/978-1-84113-584-7"><bdi>978-1-84113-584-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=International+Domain+Name+Law%3A+ICANN+and+the+UDRP&rft.pages=8&rft.pub=Bloomsbury+Publishing&rft.date=2007&rft.isbn=978-1-84113-584-7&rft.aulast=Lindsay&rft.aufirst=David&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-rfc4343-27"><a href="#cite_ref-rfc4343_27-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFD._Eastlake_III2006" class="citation cs1">D. Eastlake III (January 2006). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4343">Domain Name System (DNS) Case Insensitivity Clarification</a>. Network Working Group. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC4343">10.17487/RFC4343</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4343">4343</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Domain+Name+System+%28DNS%29+Case+Insensitivity+Clarification&rft.pub=Network+Working+Group&rft.date=2006-01&rft_id=info%3Adoi%2F10.17487%2FRFC4343&rft.au=D.+Eastlake+III&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc4343&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> Proposed Standard. Updated by <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5890">5890</a>. Updates <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">1034</a>, <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1035">1035</a> and <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2181">2181</a>. </li> <li id="cite_note-rfc3696-28">^ <a href="#cite_ref-rfc3696_28-0">a</a> <a href="#cite_ref-rfc3696_28-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJ._Klensin2004" class="citation cs1"><a href="/wiki/John_Klensin" title="John Klensin">J. Klensin</a> (February 2004). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3696">Application Techniques for Checking and Transformation of Names</a>. Network Working Group. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC3696">10.17487/RFC3696</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3696">3696</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Application+Techniques+for+Checking+and+Transformation+of+Names&rft.pub=Network+Working+Group&rft.date=2004-02&rft_id=info%3Adoi%2F10.17487%2FRFC3696&rft.au=J.+Klensin&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc3696&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> Informational. </li> <li id="cite_note-29"><a href="#cite_ref-29">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFujiwaraSullivanHoffman2024" class="citation journal cs1">Fujiwara, Kazunori; Sullivan, Andrew; Hoffman, Paul (2024). <a rel="nofollow" class="external text" href="https://www.rfc-editor.org/rfc/rfc9499.html#section-6-4.42">"DNS Terminology"</a>. tools.ietf.org. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC9499">10.17487/RFC9499</a>. Retrieved 2024-07-01.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=tools.ietf.org&rft.atitle=DNS+Terminology&rft.date=2024&rft_id=info%3Adoi%2F10.17487%2FRFC9499&rft.aulast=Fujiwara&rft.aufirst=Kazunori&rft.au=Sullivan%2C+Andrew&rft.au=Hoffman%2C+Paul&rft_id=https%3A%2F%2Fwww.rfc-editor.org%2Frfc%2Frfc9499.html%23section-6-4.42&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-30"><a href="#cite_ref-30">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNemethSnyderHein2006" class="citation book cs1">Nemeth, Evi; Snyder, Garth; Hein, Trent R. (2006-10-30). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=GB_O89fnz_sC&dq=%22lame+delegation%22&pg=PA475">Linux Administration Handbook</a>. Addison-Wesley Professional. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-13-700275-7" title="Special:BookSources/978-0-13-700275-7"><bdi>978-0-13-700275-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Linux+Administration+Handbook&rft.pub=Addison-Wesley+Professional&rft.date=2006-10-30&rft.isbn=978-0-13-700275-7&rft.aulast=Nemeth&rft.aufirst=Evi&rft.au=Snyder%2C+Garth&rft.au=Hein%2C+Trent+R.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DGB_O89fnz_sC%26dq%3D%2522lame%2Bdelegation%2522%26pg%3DPA475&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-31"><a href="#cite_ref-31">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBissyandeSie2017" class="citation book cs1">Bissyande, Tegawendé F.; Sie, Oumarou (2017-10-09). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=YjE5DwAAQBAJ&dq=%22lame+delegation%22&pg=PA235">e-Infrastructure and e-Services for Developing Countries: 8th International Conference, AFRICOMM 2016, Ouagadougou, Burkina Faso, December 6-7, 2016, Proceedings</a>. Springer. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-319-66742-3" title="Special:BookSources/978-3-319-66742-3"><bdi>978-3-319-66742-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=e-Infrastructure+and+e-Services+for+Developing+Countries%3A+8th+International+Conference%2C+AFRICOMM+2016%2C+Ouagadougou%2C+Burkina+Faso%2C+December+6-7%2C+2016%2C+Proceedings&rft.pub=Springer&rft.date=2017-10-09&rft.isbn=978-3-319-66742-3&rft.aulast=Bissyande&rft.aufirst=Tegawend%C3%A9+F.&rft.au=Sie%2C+Oumarou&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DYjE5DwAAQBAJ%26dq%3D%2522lame%2Bdelegation%2522%26pg%3DPA235&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-32"><a href="#cite_ref-32">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.ionos.co.uk/digitalguide/server/know-how/dns-zone/">"DNS zone"</a>. IONOS Digitalguide. 27 January 2022. Retrieved 2022-03-31.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=IONOS+Digitalguide&rft.atitle=DNS+zone&rft.date=2022-01-27&rft_id=https%3A%2F%2Fwww.ionos.co.uk%2Fdigitalguide%2Fserver%2Fknow-how%2Fdns-zone%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-33"><a href="#cite_ref-33">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.ionos.com/digitalguide/server/know-how/dns-propagation/">"What is DNS propagation?"</a>. IONOS Digitalguide. Retrieved 2022-04-22.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=IONOS+Digitalguide&rft.atitle=What+is+DNS+propagation%3F&rft_id=https%3A%2F%2Fwww.ionos.com%2Fdigitalguide%2Fserver%2Fknow-how%2Fdns-propagation%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-34"><a href="#cite_ref-34">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://ask.slashdot.org/story/05/04/18/198259/providers-ignoring-dns-ttl">"Providers ignoring DNS TTL?"</a>. <a href="/wiki/Slashdot" title="Slashdot">Slashdot</a>. 2005. Retrieved 2012-04-07.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Providers+ignoring+DNS+TTL%3F&rft.pub=Slashdot&rft.date=2005&rft_id=http%3A%2F%2Fask.slashdot.org%2Fstory%2F05%2F04%2F18%2F198259%2Fproviders-ignoring-dns-ttl&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-35"><a href="#cite_ref-35">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBen_Anderson2011" class="citation web cs1">Ben Anderson (7 September 2011). <a rel="nofollow" class="external text" href="http://dyn.com/web-browser-dns-caching-bad-thing/">"Ben Anderson: Why Web Browser DNS Caching Can Be A Bad Thing"</a>. Retrieved 20 October 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Ben+Anderson%3A+Why+Web+Browser+DNS+Caching+Can+Be+A+Bad+Thing&rft.date=2011-09-07&rft.au=Ben+Anderson&rft_id=http%3A%2F%2Fdyn.com%2Fweb-browser-dns-caching-bad-thing%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-36"><a href="#cite_ref-36">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://support.microsoft.com/default.aspx?scid=KB;en-us;263558">"How Internet Explorer uses the cache for DNS host entries"</a>. <a href="/wiki/Microsoft_Corporation" class="mw-redirect" title="Microsoft Corporation">Microsoft Corporation</a>. 2004. Retrieved 2010-07-25.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=How+Internet+Explorer+uses+the+cache+for+DNS+host+entries&rft.pub=Microsoft+Corporation&rft.date=2004&rft_id=http%3A%2F%2Fsupport.microsoft.com%2Fdefault.aspx%3Fscid%3DKB%3Ben-us%3B263558&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-37"><a href="#cite_ref-37">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6">"Domain Name System (DNS) Parameters"</a>. <a href="/wiki/IANA" class="mw-redirect" title="IANA">IANA</a>. DNS RCODEs. Retrieved 14 June 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Domain+Name+System+%28DNS%29+Parameters&rft.pages=DNS+RCODEs&rft.pub=IANA&rft_id=https%3A%2F%2Fwww.iana.org%2Fassignments%2Fdns-parameters%2Fdns-parameters.xhtml%23dns-parameters-6&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-38"><a href="#cite_ref-38">^</a> James F. Kurose and Keith W. Ross, Computer Networking: A Top-Down Approach, 6th ed. Essex, England: Pearson Educ. Limited, 2012 </li> <li id="cite_note-39"><a href="#cite_ref-39">^</a> RFC 5395, Domain Name System (DNS) IANA Considerations, D. Eastlake 3rd (November 2008), Section 3 </li> <li id="cite_note-40"><a href="#cite_ref-40">^</a> RFC 5395, Domain Name System (DNS) IANA Considerations, D. Eastlake 3rd (November 2008), p. 11 </li> <li id="cite_note-rfc4592-41">^ <a href="#cite_ref-rfc4592_41-0">a</a> <a href="#cite_ref-rfc4592_41-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4592">4592</a>, The Role of Wildcards in the Domain Name System, E. Lewis (July 2006) </li> <li id="cite_note-rfc2136-42"><a href="#cite_ref-rfc2136_42-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFS._ThomsonY._RekhterJ._Bound1997" class="citation cs1">S. Thomson; Y. Rekhter; J. Bound (April 1997). <a href="/wiki/Paul_Vixie" title="Paul Vixie">P. Vixie</a> (ed.). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2136">Dynamic Updates in the Domain Name System (DNS UPDATE)</a>. Network Working Group. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC2136">10.17487/RFC2136</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2136">2136</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Dynamic+Updates+in+the+Domain+Name+System+%28DNS+UPDATE%29&rft.pub=Network+Working+Group&rft.date=1997-04&rft_id=info%3Adoi%2F10.17487%2FRFC2136&rft.au=S.+Thomson&rft.au=Y.+Rekhter&rft.au=J.+Bound&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc2136&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> Proposed Standard. Updates <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1035">1035</a>. Updated by <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3007">3007</a>, <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4033">4033</a>, <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4034">4034</a> and <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4035">4035</a>. </li> <li id="cite_note-43"><a href="#cite_ref-43">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2671">2671</a>, Extension Mechanisms for DNS (EDNS0), P. Vixie (August 1999) </li> <li id="cite_note-44"><a href="#cite_ref-44">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCsikorDivakaran2021" class="citation web cs1">Csikor, Levente; Divakaran, Dinil Mon (February 2021). <a rel="nofollow" class="external text" href="https://raw.githubusercontent.com/cslev/doh_ml/main/DNS_over_HTTPS_identification.pdf">"Privacy of DNS over HTTPS: Requiem for a Dream?"</a> (PDF). National University of Singapore. <q>We investigate whether DoH traffic is distinguishable from encrypted Web traffic. To this end, we train a machine learning model to classify HTTPS traffic as either Web or DoH. With our DoH identification model in place, we show that an authoritarian ISP can identify ≈97.4% of the DoH packets correctly while only misclassifying 1 in 10,000 Web packets.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Privacy+of+DNS+over+HTTPS%3A+Requiem+for+a+Dream%3F&rft.pub=National+University+of+Singapore&rft.date=2021-02&rft.aulast=Csikor&rft.aufirst=Levente&rft.au=Divakaran%2C+Dinil+Mon&rft_id=https%3A%2F%2Fraw.githubusercontent.com%2Fcslev%2Fdoh_ml%2Fmain%2FDNS_over_HTTPS_identification.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-45"><a href="#cite_ref-45">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHuitemaDickinsonMankin2022" class="citation cs1">Huitema, Christian; Dickinson, Sara; Mankin, Allison (May 2022). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9250">DNS over Dedicated QUIC Connections</a>. Internet Engineering Task Force. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC9250">10.17487/RFC9250</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9250">9250</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=DNS+over+Dedicated+QUIC+Connections&rft.pub=Internet+Engineering+Task+Force&rft.date=2022-05&rft_id=info%3Adoi%2F10.17487%2FRFC9250&rft.aulast=Huitema&rft.aufirst=Christian&rft.au=Dickinson%2C+Sara&rft.au=Mankin%2C+Allison&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc9250&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-46"><a href="#cite_ref-46">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchmittEdmundsonFeamster2019" class="citation journal cs1">Schmitt, Paul; Edmundson, Anne; Feamster, Nick (2019). <a rel="nofollow" class="external text" href="https://petsymposium.org/2019/files/papers/issue2/popets-2019-0028.pdf">"Oblivious DNS: Practical Privacy for DNS Queries"</a> (PDF). Privacy Enhancing Technologies. 2019 (2): 228–244. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1806.00276">1806.00276</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.2478%2Fpopets-2019-0028">10.2478/popets-2019-0028</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:44126163">44126163</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20220121210624/https://petsymposium.org/2019/files/papers/issue2/popets-2019-0028.pdf">Archived</a> (PDF) from the original on 2022-01-21.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Privacy+Enhancing+Technologies&rft.atitle=Oblivious+DNS%3A+Practical+Privacy+for+DNS+Queries&rft.volume=2019&rft.issue=2&rft.pages=228-244&rft.date=2019&rft_id=info%3Aarxiv%2F1806.00276&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A44126163%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.2478%2Fpopets-2019-0028&rft.aulast=Schmitt&rft.aufirst=Paul&rft.au=Edmundson%2C+Anne&rft.au=Feamster%2C+Nick&rft_id=https%3A%2F%2Fpetsymposium.org%2F2019%2Ffiles%2Fpapers%2Fissue2%2Fpopets-2019-0028.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-47"><a href="#cite_ref-47">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://medium.com/noise-lab/oblivious-dns-deployed-by-cloudflare-and-apple-1522ccf53cab">"Oblivious DNS Deployed by Cloudflare and Apple"</a>. 9 December 2020. Retrieved 27 July 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Oblivious+DNS+Deployed+by+Cloudflare+and+Apple&rft.date=2020-12-09&rft_id=https%3A%2F%2Fmedium.com%2Fnoise-lab%2Foblivious-dns-deployed-by-cloudflare-and-apple-1522ccf53cab&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-48"><a href="#cite_ref-48">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPauly2021" class="citation web cs1">Pauly, Tommy (2 September 2021). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/draft-pauly-dprive-oblivious-doh/">"Oblivious DNS Over HTTPS"</a>. IETF.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Oblivious+DNS+Over+HTTPS&rft.pub=IETF&rft.date=2021-09-02&rft.aulast=Pauly&rft.aufirst=Tommy&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fdraft-pauly-dprive-oblivious-doh%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-49"><a href="#cite_ref-49">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMuffett2021" class="citation web cs1">Muffett, Alec (February 2021). <a rel="nofollow" class="external text" href="https://www.ndss-symposium.org/wp-content/uploads/dnspriv21-03-paper.pdf">""No Port 53, Who Dis?" A Year of DNS over HTTPS over Tor"</a> (PDF). Network and Distributed System Security Symposium. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210321110839/https://www.ndss-symposium.org/wp-content/uploads/dnspriv21-03-paper.pdf">Archived</a> (PDF) from the original on 2021-03-21. <q>DNS over HTTPS (DoH) obviates many but not all of the risks, and its transport protocol (i.e. HTTPS) raises concerns of privacy due to (e.g.) 'cookies.' The Tor Network exists to provide TCP circuits with some freedom from tracking, surveillance, and blocking. Thus: In combination with Tor, DoH, and the principle of "Don't Do That, Then" (DDTT) to mitigate request fingerprinting, I describe DNS over HTTPS over Tor (DoHoT).</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=%22No+Port+53%2C+Who+Dis%3F%22+A+Year+of+DNS+over+HTTPS+over+Tor&rft.pub=Network+and+Distributed+System+Security+Symposium&rft.date=2021-02&rft.aulast=Muffett&rft.aufirst=Alec&rft_id=https%3A%2F%2Fwww.ndss-symposium.org%2Fwp-content%2Fuploads%2Fdnspriv21-03-paper.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-50"><a href="#cite_ref-50">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUlevitch2011" class="citation web cs1">Ulevitch, David (6 December 2011). <a rel="nofollow" class="external text" href="https://umbrella.cisco.com/blog/dnscrypt-critical-fundamental-and-about-time">"DNSCrypt – Critical, fundamental, and about time"</a>. Cisco Umbrella. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200701221715/https://umbrella.cisco.com/blog/dnscrypt-critical-fundamental-and-about-time">Archived</a> from the original on 1 July 2020.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Cisco+Umbrella&rft.atitle=DNSCrypt+%E2%80%93+Critical%2C+fundamental%2C+and+about+time.&rft.date=2011-12-06&rft.aulast=Ulevitch&rft.aufirst=David&rft_id=https%3A%2F%2Fumbrella.cisco.com%2Fblog%2Fdnscrypt-critical-fundamental-and-about-time&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-Anonymized_DNSCrypt_specification-51"><a href="#cite_ref-Anonymized_DNSCrypt_specification_51-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://raw.githubusercontent.com/DNSCrypt/dnscrypt-protocol/master/ANONYMIZED-DNSCRYPT.txt">"Anonymized DNSCrypt specification"</a>. <a href="/wiki/GitHub" title="GitHub">GitHub</a>. DNSCrypt. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20191025094649/https://raw.githubusercontent.com/DNSCrypt/dnscrypt-protocol/master/ANONYMIZED-DNSCRYPT.txt">Archived</a> from the original on 25 October 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=GitHub&rft.atitle=Anonymized+DNSCrypt+specification&rft_id=https%3A%2F%2Fraw.githubusercontent.com%2FDNSCrypt%2Fdnscrypt-protocol%2Fmaster%2FANONYMIZED-DNSCRYPT.txt&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-ODoH_(2022)-52"><a href="#cite_ref-ODoH_(2022)_52-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://github.com/DNSCrypt/dnscrypt-proxy/wiki/Oblivious-DoH">"Oblivious DoH · DNSCrypt/dnscrypt-proxy Wiki"</a>. GitHub. DNSCrypt project. Retrieved 28 July 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=GitHub&rft.atitle=Oblivious+DoH+%C2%B7+DNSCrypt%2Fdnscrypt-proxy+Wiki&rft_id=https%3A%2F%2Fgithub.com%2FDNSCrypt%2Fdnscrypt-proxy%2Fwiki%2FOblivious-DoH&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-53"><a href="#cite_ref-53">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHerzbergShulman2014" class="citation journal cs1">Herzberg, Amir; Shulman, Haya (2014-01-01). <a rel="nofollow" class="external text" href="https://ieeexplore.ieee.org/document/6756846">"Retrofitting Security into Network Protocols: The Case of DNSSEC"</a>. IEEE Internet Computing. 18 (1): 66–71. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FMIC.2014.14">10.1109/MIC.2014.14</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1089-7801">1089-7801</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:12230888">12230888</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Internet+Computing&rft.atitle=Retrofitting+Security+into+Network+Protocols%3A+The+Case+of+DNSSEC&rft.volume=18&rft.issue=1&rft.pages=66-71&rft.date=2014-01-01&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A12230888%23id-name%3DS2CID&rft.issn=1089-7801&rft_id=info%3Adoi%2F10.1109%2FMIC.2014.14&rft.aulast=Herzberg&rft.aufirst=Amir&rft.au=Shulman%2C+Haya&rft_id=https%3A%2F%2Fieeexplore.ieee.org%2Fdocument%2F6756846&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-54"><a href="#cite_ref-54">^</a> APWG. "Global Phishing Survey: Domain Name Use and Trends in 1H2010." <a rel="nofollow" class="external text" href="http://www.apwg.org/reports/APWG_GlobalPhishingSurvey_1H2010.pdf">10/15/2010 apwg.org</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20121003212327/http://apwg.org/reports/APWG_GlobalPhishingSurvey_1H2010.pdf">Archived</a> 2012-10-03 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> </li> <li id="cite_note-Huston-2019-55">^ <a href="#cite_ref-Huston-2019_55-0">a</a> <a href="#cite_ref-Huston-2019_55-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHuston2019" class="citation journal cs1">Huston, Geoff (July 2019). <a rel="nofollow" class="external text" href="http://ipj.dreamhosters.com/wp-content/uploads/2019/07/ipj222.pdf">"DNS Privacy and the IETF"</a> (PDF). The Internet Protocol Journal. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20190930154208/http://ipj.dreamhosters.com/wp-content/uploads/2019/07/ipj222.pdf">Archived</a> (PDF) from the original on 2019-09-30.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Internet+Protocol+Journal&rft.atitle=DNS+Privacy+and+the+IETF&rft.date=2019-07&rft.aulast=Huston&rft.aufirst=Geoff&rft_id=http%3A%2F%2Fipj.dreamhosters.com%2Fwp-content%2Fuploads%2F2019%2F07%2Fipj222.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-56"><a href="#cite_ref-56">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20151222144443/https://www.icann.org/news/announcement-2015-12-03-en">"Registration Data Access Protocol (RDAP) Operational Profile for gTLD Registries and Registrars"</a>. <a href="/wiki/ICANN" title="ICANN">ICANN</a>. 3 December 2015. Archived from <a rel="nofollow" class="external text" href="https://www.icann.org/news/announcement-2015-12-03-en">the original</a> on 22 December 2015. Retrieved 18 December 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Registration+Data+Access+Protocol+%28RDAP%29+Operational+Profile+for+gTLD+Registries+and+Registrars&rft.pub=ICANN&rft.date=2015-12-03&rft_id=https%3A%2F%2Fwww.icann.org%2Fnews%2Fannouncement-2015-12-03-en&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> <li id="cite_note-57"><a href="#cite_ref-57">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.verisign.com/en_US/domain-names/domain-registrar/index.xhtml">"Find a Registrar"</a>. VeriSign, Inc. Retrieved 18 December 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Find+a+Registrar&rft.pub=VeriSign%2C+Inc.&rft_id=http%3A%2F%2Fwww.verisign.com%2Fen_US%2Fdomain-names%2Fdomain-registrar%2Findex.xhtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"> </li> </ol></div> <div class="mw-heading mw-heading3"><h3 id="Sources">Sources</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=37" title="Edit section: Sources">edit</a>]</div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEvans2018" class="citation book cs1">Evans, Claire L. (2018). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=C8ouDwAAQBAJ&q=9780735211759&pg=PP1">Broad Band: The Untold Story of the Women Who Made the Internet</a>. New York: Portfolio/Penguin. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780735211759" title="Special:BookSources/9780735211759"><bdi>9780735211759</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Broad+Band%3A+The+Untold+Story+of+the+Women+Who+Made+the+Internet&rft.place=New+York&rft.pub=Portfolio%2FPenguin&rft.date=2018&rft.isbn=9780735211759&rft.aulast=Evans&rft.aufirst=Claire+L.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DC8ouDwAAQBAJ%26q%3D9780735211759%26pg%3DPP1&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"></li></ul> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=38" title="Edit section: Further reading">edit</a>]</div> <div class="mw-heading mw-heading3"><h3 id="Standards_track">Standards track</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=39" title="Edit section: Standards track">edit</a>]</div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1034">1034</a>, Domain Names - Concepts and Facilities</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1035">1035</a>, Domain Names - Implementation and Specification</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1123">1123</a>, Requirements for Internet Hosts—Application and Support</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1995">1995</a>, Incremental Zone Transfer in DNS</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1996">1996</a>, A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2136">2136</a>, Dynamic Updates in the domain name system (DNS UPDATE)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2181">2181</a>, Clarifications to the DNS Specification</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2308">2308</a>, Negative Caching of DNS Queries (DNS NCACHE)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3225">3225</a>, Indicating Resolver Support of DNSSEC</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3226">3226</a>, DNSSEC and IPv6 A6 aware server/resolver message size requirements</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3596">3596</a>, DNS Extensions to Support IP Version 6</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3597">3597</a>, Handling of Unknown DNS Resource Record (RR) Types</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4343">4343</a>, Domain Name System (DNS) Case Insensitivity Clarification</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4592">4592</a>, The Role of Wildcards in the Domain Name System</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4635">4635</a>, HMAC SHA TSIG Algorithm Identifiers</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5001">5001</a>, DNS Name Server Identifier (NSID) Option</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5011">5011</a>, Automated Updates of DNS Security (DNSSEC) Trust Anchors</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5452">5452</a>, Measures for Making DNS More Resilient against Forged Answers</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5890">5890</a>, Internationalized Domain Names for Applications (IDNA):Definitions and Document Framework</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5891">5891</a>, Internationalized Domain Names in Applications (IDNA): Protocol</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5892">5892</a>, The Unicode Code Points and Internationalized Domain Names for Applications (IDNA)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5893">5893</a>, Right-to-Left Scripts for Internationalized Domain Names for Applications (IDNA)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc6672">6672</a>, Non-Terminal DNS Name Redirection</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc6891">6891</a>, Extension Mechanisms for DNS (EDNS0)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7766">7766</a>, DNS Transport over TCP - Implementation Requirements</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8945">8945</a>, Secret Key Transaction Authentication for DNS (TSIG)</li></ul> <div class="mw-heading mw-heading3"><h3 id="Proposed_security_standards">Proposed security standards</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=40" title="Edit section: Proposed security standards">edit</a>]</div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4033">4033</a>, DNS Security Introduction and Requirements</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4034">4034</a>, Resource Records for the DNS Security Extensions</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4035">4035</a>, Protocol Modifications for the DNS Security Extensions</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4509">4509</a>, Use of SHA-256 in DNSSEC Delegation Signer (DS) Resource Records</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4470">4470</a>, Minimally Covering NSEC Records and DNSSEC On-line Signing</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5155">5155</a>, DNS Security (DNSSEC) Hashed Authenticated Denial of Existence</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5702">5702</a>, Use of SHA-2 Algorithms with RSA in DNSKEY and RRSIG Resource Records for DNSSEC</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5910">5910</a>, Domain Name System (DNS) Security Extensions Mapping for the Extensible Provisioning Protocol (EPP)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5933">5933</a>, Use of GOST Signature Algorithms in DNSKEY and RRSIG Resource Records for DNSSEC</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7830">7830</a>, The EDNS(0) Padding Option</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7858">7858</a>, Specification for DNS over Transport Layer Security (TLS)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8310">8310</a>, Usage Profiles for DNS over TLS and DNS over DTLS</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8484">8484</a>, DNS Queries over HTTPS (DoH)</li></ul> <div class="mw-heading mw-heading3"><h3 id="Experimental_RFCs">Experimental RFCs</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=41" title="Edit section: Experimental RFCs">edit</a>]</div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1183">1183</a>, New DNS RR Definitions</li></ul> <div class="mw-heading mw-heading3"><h3 id="Best_Current_Practices">Best Current Practices</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=42" title="Edit section: Best Current Practices">edit</a>]</div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2182">2182</a>, Selection and Operation of Secondary DNS Servers (BCP 16)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2317">2317</a>, Classless IN-ADDR.ARPA delegation (BCP 20)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5625">5625</a>, DNS Proxy Implementation Guidelines (BCP 152)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc6895">6895</a>, Domain Name System (DNS) IANA Considerations (BCP 42)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7720">7720</a>, DNS Root Name Service Protocol and Deployment Requirements (BCP 40)</li></ul> <div class="mw-heading mw-heading3"><h3 id="Informational_RFCs">Informational RFCs</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=43" title="Edit section: Informational RFCs">edit</a>]</div> These RFCs are advisory in nature, but may provide useful information despite defining neither a standard or BCP. (RFC 1796) <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1178">1178</a>, Choosing a Name for Your Computer (FYI 5)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1591">1591</a>, Domain Name System Structure and Delegation</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1912">1912</a>, Common DNS Operational and Configuration Errors</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2100">2100</a>, The Naming of Hosts</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3696">3696</a>, Application Techniques for Checking and Transformation of Names</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3833">3833</a>. Threat Analysis of the Domain Name System (DNS)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4892">4892</a>, Requirements for a Mechanism Identifying a Name Server Instance</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5894">5894</a>, Internationalized Domain Names for Applications (IDNA):Background, Explanation, and Rationale</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5895">5895</a>, Mapping Characters for Internationalized Domain Names in Applications (IDNA) 2008</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8806">8806</a>, Running a Root Server Local to a Resolver</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9076">9076</a>, DNS Privacy Considerations</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9156">9156</a>, DNS Query Name Minimisation to Improve Privacy</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9499">9499</a>, DNS Terminology</li></ul> <div class="mw-heading mw-heading3"><h3 id="Unknown">Unknown</h3>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=44" title="Edit section: Unknown">edit</a>]</div> These RFCs have an official status of <a href="/wiki/Request_for_Comments#Unknown" title="Request for Comments">Unknown</a>, but due to their age are not clearly labeled as such. <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc920">920</a>, Domain Requirements – Specified original top-level domains</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1032">1032</a>, Domain Administrators Guide</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1033">1033</a>, Domain Administrators Operations Guide</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1101">1101</a>, DNS Encodings of Network Names and Other Types</li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2>[<a href="/w/index.php?title=Domain_Name_System&action=edit&section=45" title="Edit section: External links">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/40px-Wikiversity_logo_2017.svg.png" decoding="async" width="40" height="33" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/60px-Wikiversity_logo_2017.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/80px-Wikiversity_logo_2017.svg.png 2x" data-file-width="626" data-file-height="512" /></div> <div class="side-box-text plainlist">Wikiversity has learning resources about <a href="https://en.wikiversity.org/wiki/Domain_Name_System" class="extiw" title="v:Domain Name System"> Domain Name System</a></div></div> </div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFVixie2007" class="citation web cs1">Vixie, Paul (4 May 2007). <a rel="nofollow" class="external text" href="https://queue.acm.org/detail.cfm?id=1242499">"DNS Complexity"</a>. <a href="/wiki/ACM_Queue" title="ACM Queue">ACM Queue</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230329160719/https://queue.acm.org/detail.cfm?id=1242499">Archived</a> from the original on 29 March 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=DNS+Complexity&rft.pub=ACM+Queue&rft.date=2007-05-04&rft.aulast=Vixie&rft.aufirst=Paul&rft_id=https%3A%2F%2Fqueue.acm.org%2Fdetail.cfm%3Fid%3D1242499&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBall2014" class="citation news cs1">Ball, James (28 February 2014). <a rel="nofollow" class="external text" href="https://www.theguardian.com/technology/2014/feb/28/seven-people-keys-worldwide-internet-security-web">"Meet the seven people who hold the keys to worldwide internet security"</a>. <a href="/wiki/The_Guardian" title="The Guardian">The Guardian</a>. Guardian News & Media Limited. Retrieved 28 February 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Guardian&rft.atitle=Meet+the+seven+people+who+hold+the+keys+to+worldwide+internet+security&rft.date=2014-02-28&rft.aulast=Ball&rft.aufirst=James&rft_id=https%3A%2F%2Fwww.theguardian.com%2Ftechnology%2F2014%2Ffeb%2F28%2Fseven-people-keys-worldwide-internet-security-web&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKruger2016" class="citation web cs1">Kruger, Lennard G. (18 November 2016). <a rel="nofollow" class="external text" href="https://sgp.fas.org/crs/misc/R42351.pdf">"Internet Governance and the Domain Name System: Issues for Congress"</a> (PDF). Congressional Research Service. Retrieved 27 July 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Congressional+Research+Service&rft.atitle=Internet+Governance+and+the+Domain+Name+System%3A+Issues+for+Congress&rft.date=2016-11-18&rft.aulast=Kruger&rft.aufirst=Lennard+G.&rft_id=https%3A%2F%2Fsgp.fas.org%2Fcrs%2Fmisc%2FR42351.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADomain+Name+System" class="Z3988"></li> <li><a rel="nofollow" class="external text" href="http://www.zytrax.com/books/dns/">Zytrax.com</a>, Open Source Guide – DNS for Rocket Scientists.</li> <li><a rel="nofollow" class="external text" href="https://messwithdns.net/">Mess with DNS</a> – site where you can do experiments with DNS.</li></ul> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox authority-control" aria-label="Navbox" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Help:Authority_control" title="Help:Authority control">Authority control databases</a>: National <a href="https://www.wikidata.org/wiki/Q8767#identifiers" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"><ul><li><a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4348318-5">Germany</a></li><li><a rel="nofollow" class="external text" href="https://id.ndl.go.jp/auth/ndlna/001311891">Japan</a></li><li><a rel="nofollow" class="external text" href="https://dbn.bn.org.pl/descriptor-details/9810532434805606">Poland</a></li></ul></div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; 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