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class="entry-title"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ssh-reverse-tunnels/" rel="bookmark">Setting up ssh reverse tunnels with reversi</a></h2> </header> <footer class="entry-footer"> <span class="posted-on"><span class="screen-reader-text">Posted on </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ssh-reverse-tunnels/" rel="bookmark"><time class="entry-date published" datetime="2017-12-22T00:41:25+00:00">December 22, 2017</time><time class="updated" datetime="2018-03-30T15:35:55+00:00">March 30, 2018</time></a></span><span class="byline"><span class="author vcard"><span class="screen-reader-text">Author </span><a class="url fn n" href="https://web.archive.org/web/20200514202132/https://comm-tech.org/author/alan/">Alan B.</a></span></span><span class="tags-links"><span class="screen-reader-text">Tags </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/how-to/" rel="tag">how-to</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/linux/" rel="tag">linux</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/reversi/" rel="tag">reversi</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/ssh/" rel="tag">ssh</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/tech-advice/" rel="tag">tech advice</a></span><span class="comments-link"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ssh-reverse-tunnels/#respond">Leave a comment</a></span> </footer> <div class="entry-content"> <p># reversi-server and reversiclient<br/> # Author: kazimof at zzero dot org</p> <p># This program is free software: you can redistribute it and/or modify<br/> # it under the terms of the GNU General Public License as published by<br/> # the Free Software Foundation, either version 3 of the License, or<br/> # (at your option) any later version.<br/> #<br/> # This program is distributed in the hope that it will be useful,<br/> # but WITHOUT ANY WARRANTY; without even the implied warranty of<br/> # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the<br/> # GNU General Public License for more details.<br/> #<br/> # http://www.gnu.org/licenses/.</p> <p>repo now moved to git.<br/> https://github.com/kazimof/reversi/</p> <p>WHAT DOES REVERSI DO?<br/> ———————<br/> Uses reverse ssh tunnels to expose device ports on a reversi-client’s network to a reversi-server anywhere on the internet.</p> <p>A reverse ssh tunnel (ssh -R) can be established quite easily, the problem comes with connection stability, where the ssh connection can and does hang from either the server or client end. Reversi tests the validity of the connection from the client every X seconds and re-establishes it if the connection is not fit for purpose.</p> <p>EXAMPLE USE 1:<br/> —————–<br/> You need to manage a LAN but you have no access to their office broadband router to configure port forwarding.</p> <p>EXAMPLE USE 2:<br/> —————–<br/> You have OpenWRT devices installed within a public mesh network and you need to be able to manage them.</p> <p>EXAMPLE USE 3:<br/> —————–<br/> A company router has died or their broadband has been cut or they have moved premises, so they are on a temporary 3/4G connection waiting for a new broadband router with a static IP. Obviously the server not getting mail since port 25 is no longer forwarded by router, and webmail is unavailable to user for the same reason. Using an openwrt inside the network I forward ports 25 and 443 of the mail server to internet allowing the company mail server to receive mail and service web mail requests.</p> <p>HOW DOES IT WORK?<br/> —————–<br/> reversi-clients are equipped with a password-free ssh key to a user on the reversi-server. Using this key the reversi-client is allowed to do 2 things:<br/> 1) run a script that forwards any local port on it’s network the reversi-server<br/> 2) run a script on the reversi-server passing arguements that inform the reversi-server about which node they are, which port it is using and what kind of response to expect from that port</p> <p>On the client side the scripts are both run in gnu-screen, one does the reverse connection and the other acts as a connections monitor, killing and re-establishing the reverse tunnel according to the server response from the script referenced in 2) above.</p> <p>On the server side the script referenced in 2) above tests to see whether the port is responding with the expected response, if not it assumes the connection has hung, identifies the appropriate PID and kills it. Script then returns a number specifying a time which the client monitor script should wait before retyring the connection.</p> <p>DESIGN PARAMETERS<br/> —————–<br/> Needs to run on a variety of client OS, I am managing a mix of hundreds of openwrt devices, linux servers and OSX installs, I needed this solution for them all and I am too lazy to maintain multiple forks.<br/> The 2 programs available to all platforms are:</p> <p>screen<br/> ssh</p> <p>DESIGN<br/> ——<br/> Reversi commprises of 2 components to be installed on the reversi server.</p> <p>SERVER: hosts a script that clients are authorised to invoke to monitor and manage their reverse tunnel<br/> RECOMMENDED INSTALL FOLDER: /home/reversi/reversi<br/> CLIENT BUILDER: builds the scripts to be run on the client device<br/> RECOMMENDED INSTALL FOLDER: /root/reversi/client-builder</p> <p>See INSTRUCTIONS.TXT for installation info.</p> </div> </article> <article id="post-543" class="post-543 post type-post status-publish format-standard hentry category-uncategorized tag-how-to tag-linux tag-tech-advice"> <header class="entry-header"> <h2 class="entry-title"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/monitoring-your-linux-servers/" rel="bookmark">Scripts for monitoring Linux servers</a></h2> </header> <footer class="entry-footer"> <span class="posted-on"><span class="screen-reader-text">Posted on </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/monitoring-your-linux-servers/" rel="bookmark"><time class="entry-date published" datetime="2017-09-03T17:39:02+00:00">September 3, 2017</time><time class="updated" datetime="2018-05-16T09:55:42+00:00">May 16, 2018</time></a></span><span class="byline"><span class="author vcard"><span class="screen-reader-text">Author </span><a class="url fn n" href="https://web.archive.org/web/20200514202132/https://comm-tech.org/author/alan/">Alan B.</a></span></span><span class="tags-links"><span class="screen-reader-text">Tags </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/how-to/" rel="tag">how-to</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/linux/" rel="tag">linux</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/tech-advice/" rel="tag">tech advice</a></span><span class="comments-link"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/monitoring-your-linux-servers/#respond">Leave a comment</a></span> </footer> <div class="entry-content"> <p>Tired of regularly logging into our servers to find out if anything is wrong, I wanted to know before something like a spam attack or a disk-eater gets out of hand.</p> <p>Wrote some scripts to automate the process and email me some stats. Yes there are tools to do this for you, but then you have to maintain those tools, and sometimes installing them and configuring them on so many servers can be a pain. This system needs only ssh and mutt, lightweight and available in almost all Linux distributions I know.</p> <p>This, it’s simply bash installed on one server, and everything is “pushed” fresh to the servers every time it is run, so updates are automatic and easily deployed.</p> <h2>Design</h2> <p>The main script checkserver.sh copies (using scp) the checkservices, checkdf, checkmailq and checkmaillog scripts and config files to the target host, runs them there and emails the output to you.</p> <p>On your host servers there is nothing to install except openssh-server. Configure your password-less ssh-keys for all the servers in ~/.ssh/config on your monitoring server with the public keys in /root/.ssh/authorized_keys on the hosts. For help with that see our article: <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/master-ssh-keys/">master-ssh-key</a></p> <h2>Scripts</h2> <p> </p> <p>To send notification emails you need a mutt wrapper, almost all distributions have mutt in their repos.</p> <h4>muttcc.sh</h4> <blockquote><p>func_muttemail () {</p> <p>#### establish current dir<br/> APPDIR=$( cd “$( dirname “$0″ )” && pwd )<br/> gotdate=`date +%Y-%m-%d-%H-%M`<br/> DEBUGLOG=”$APPDIR/functions-email.log”<br/> echo “ENTERING mutt.sh” | tee -a $DEBUGLOG</p> <p>#### ASSIGN VARS<br/> mailentity=”$1″<br/> mailsubject=”$2″<br/> maildatafile=”$3″<br/> mailentitycc=”$4″<br/> echo “$mailentity $mailsubject $maildatafile” | tee -a $DEBUGFILE<br/> #send email<br/> echo “cc specified: $4″ | tee -a $DEBUGLOG<br/> if [ x”${mailentitycc}” = x ]<br/> then<br/> #the cc is not set so do not include mecc<br/> mutt -F $APPDIR/muttrc -s “$mailsubject” “$mailentity” < $maildatafile<br/> echo “no cc specified: $mailentitycc” | tee -a $DEBUGLOG<br/> else<br/> mutt -F $APPDIR/muttrc -s “$mailsubject” -c “$mailentitycc” “$mailentity” < $maildatafile<br/> echo “cc specified: $mailentitycc” | tee -a $DEBUGLOG<br/> fi</p> <p>EX=$?<br/> echo “$EX”<br/> echo “##### EXITING mutt.sh #######” | tee -a $DEBUGLOG<br/> return $EX<br/> }</p></blockquote> <p>You’ll need to install mutt and have access to an smtp server. Mine is local and needs no authentication. Normally this fill will be the user’s “.muttrc” file, but in the wrapper we have specified it’s location.</p> <h4>muttrc</h4> <blockquote><p>set from = “me@myserver.net”<br/> set realname = “CHECKSERVER”<br/> set use_envelope_from = yes<br/> set smtp_url=smtp://mylocalmailserverhostname.net/<br/> set ssl_starttls = no</p></blockquote> <h4>checkservers.sh</h4> <blockquote><p>#!/bin/bash<br/> APPDIR=$( cd “$( dirname “$0″ )” && pwd )<br/> . /$APPDIR/muttcc.sh<br/> SERVERLIST=$APPDIR/server.list<br/> MAILQTESTS=$APPDIR/checkmailq.txt<br/> MAILLOGTESTS=$APPDIR/checkmaillog.txt<br/> MAILQSH=$APPDIR/checkmailq.sh<br/> MAILLOGSH=$APPDIR/checkmaillog.sh<br/> DISKDF=$APPDIR/checkdiskdf.sh<br/> CHECKLOG=/tmp/servercheck.log</p> <p>while IFS=”:” read servername ifmailq ifmaillog ifdiskdf serviceslist<br/> do<br/> echo “=========== SERVERCHECK STARTS: $servername ==============”<br/> echo “=========== SERVERCHECK STARTS: $servername ==============” > $CHECKLOG<br/> echo “———————- disks —————— ” >> $CHECKLOG<br/> if [ “$ifdiskdf” == “diskdf” ]<br/> then<br/> scp $APPDIR/checkdiskdf.sh root@$servername:/usr/local/sbin/<br/> ssh -n root@$servername /usr/local/sbin/checkdiskdf.sh >> $CHECKLOG<br/> else<br/> echo “$servername diskdf not flagged for check” >> $CHECKLOG</p> <p>fi<br/> echo “———————- services —————— ” >> $CHECKLOG<br/> echo “SERVICEFILE: $serviceslist”<br/> case $serviceslist in<br/> no)<br/> echo “$servername services not flagged for check” >> $CHECKLOG<br/> ;;<br/> *)<br/> scp $APPDIR/checkservices-$serviceslist.txt root@$servername:/usr/local/sbin/checkservices.txt<br/> scp $APPDIR/checkservices.sh root@$servername:/usr/local/sbin/<br/> ssh -n root@$servername /usr/local/sbin/checkservices.sh >> $CHECKLOG<br/> esac</p> <p>echo “———————- mailq —————— ” >> $CHECKLOG<br/> if [ “$ifmailq” == “mailq” ]<br/> then<br/> scp $APPDIR/checkmailq.sh root@$servername:/usr/local/sbin/<br/> scp $APPDIR/checkmailq.txt root@$servername:/usr/local/sbin/<br/> ssh -n root@$servername /usr/local/sbin/checkmailq.sh >> $CHECKLOG<br/> else<br/> echo “$servername mailq not flagged for check” >> $CHECKLOG<br/> fi</p> <p>echo “—————– maillog —————– ” >> $CHECKLOG<br/> if [ “$ifmaillog” == “maillog” ]<br/> then<br/> scp $APPDIR/checkmaillog.sh root@$servername:/usr/local/sbin/<br/> scp $APPDIR/checkmaillog.txt root@$servername:/usr/local/sbin/<br/> ssh -n root@$servername /usr/local/sbin/checkmaillog.sh >> $CHECKLOG<br/> else<br/> echo “$servername maillog not flagged for check” >> $CHECKLOG<br/> fi<br/> echo “=========== SERVERCHECK ENDS: $servername ==============” >> $CHECKLOG<br/> email_subject=”checkserver results: $servername”<br/> echo “$email_subject”<br/> tmp2=$(func_muttemail “myemail@address.com” “$email_subject” “$CHECKLOG” “ccemail@address.com”)<br/> echo “=========== SERVERCHECK ENDS: $servername ==============”</p> <p>done < “$SERVERLIST”</p></blockquote> <h4>checkdiskdf.sh</h4> <blockquote><p>#!/bin/bash<br/> /bin/df -h<br/> exit</p></blockquote> <h4>checkmaillog.sh</h4> <blockquote><p>#!/bin/bash<br/> APPDIR=$( cd “$( dirname “$0″ )” && pwd )<br/> #greps maillotgs and mailqueue fiels for various issues<br/> MAILLOGTESTS=$APPDIR/checkmaillog.txt<br/> MAILRESULT=$APPDIR/checkmailresult.log<br/> MAILRESULTREPORT=$APPDIR/checkmailresult.log<br/> MAILRESULTTEMP=$APPDIR/checkmailresulttemp.log<br/> rm $MAILRESULTTEMP<br/> while IFS=”:” read testname before after<br/> do<br/> datum=`date “+%b %d”`<br/> grep -A$after -B$before “$testname” /var/log/maillog | grep “$datum” >> $MAILRESULTTEMP</p> <p>done < $MAILLOGTESTS<br/> resultlength=$(cat “$MAILRESULTTEMP” | wc -l)<br/> echo “$resultlength”<br/> if [ “$resultlength” -gt “1” ]<br/> then<br/> echo “issues found”<br/> echo “mail log errors found. lines=$resultlength.” > $MAILRESULTREPORT<br/> cat “$MAILRESULTTEMP” >> $MAILRESULTREPORT<br/> cat “$MAILRESULTREPORT”<br/> else<br/> echo “nothing to report”<br/> fi</p></blockquote> <h4>checkmaillog.txt</h4> <blockquote><p>refused to talk to me:0:0<br/> Connection timed out:0:0<br/> Name service error for name:0:0<br/> sender non-delivery notification:0:0<br/> to=<noreply@:0:0<br/> 421 Too many concurrent SMTP connections:0:0<br/> testing something:0:0</p></blockquote> <h4>checkmailq.sh</h4> <blockquote><p>#!/bin/bash<br/> APPDIR=$( cd “$( dirname “$0″ )” && pwd )<br/> #greps maillotgs and mailqueue fiels for various issues</p> <p>MAILQTESTS=$APPDIR/checkmailq.txt<br/> MAILRESULT=$APPDIR/checkmailresult.log<br/> MAILRESULTREPORT=$APPDIR/checkmailresult.log<br/> MAILRESULTTEMP=$APPDIR/checkmailresulttemp.log<br/> rm $MAILRESULTTEMP</p> <p>while IFS=”:” read testname before after<br/> do<br/> /usr/bin/mailq | grep -A$after -B$before “$testname” >> $MAILRESULTTEMP<br/> done < $MAILQTESTS<br/> resultlength=$(cat “$MAILRESULTTEMP” | wc -l)<br/> echo “$resultlength”<br/> if [ “$resultlength” -gt “1” ]<br/> then<br/> echo “issues found”<br/> echo “there is queued mail. lines=$resultlength.” > $MAILRESULTREPORT<br/> cat “$MAILRESULTTEMP” >> $MAILRESULTREPORT<br/> cat “$MAILRESULTREPORT”<br/> else<br/> echo “nothing to report”<br/> fi</p></blockquote> <h4>checkmailq.sh</h4> <blockquote><p>#!/bin/bash<br/> APPDIR=$( cd “$( dirname “$0″ )” && pwd )<br/> #greps maillotgs and mailqueue fiels for various issues</p> <p>MAILQTESTS=$APPDIR/checkmailq.txt<br/> MAILRESULT=$APPDIR/checkmailresult.log<br/> MAILRESULTREPORT=$APPDIR/checkmailresult.log<br/> MAILRESULTTEMP=$APPDIR/checkmailresulttemp.log<br/> rm $MAILRESULTTEMP</p> <p>while IFS=”:” read testname before after<br/> do<br/> /usr/bin/mailq | grep -A$after -B$before “$testname” >> $MAILRESULTTEMP<br/> done < $MAILQTESTS<br/> resultlength=$(cat “$MAILRESULTTEMP” | wc -l)<br/> echo “$resultlength”<br/> if [ “$resultlength” -gt “1” ]<br/> then<br/> echo “issues found”<br/> echo “there is queued mail. lines=$resultlength.” > $MAILRESULTREPORT<br/> cat “$MAILRESULTTEMP” >> $MAILRESULTREPORT<br/> cat “$MAILRESULTREPORT”<br/> else<br/> echo “nothing to report”<br/> fi</p></blockquote> <h4>checkmailq.txt</h4> <blockquote><p>Connection timed out:1:1<br/> Connection refused:1:1</p></blockquote> <h4>checkservices.sh</h4> <blockquote><p>#!/bin/bash</p> <p>#!/bin/bash</p> <p>APPDIR=$( cd “$( dirname “$0″ )” && pwd )</p> <p>#greps maillotgs and mailqueue fiels for various issues</p> <p>SERVICETESTS=$APPDIR/checkservices.txt</p> <p>RESULTREPORT=$APPDIR/checkservicesresultreport.log</p> <p>RESULTTEMP=$APPDIR/checkservicesresulttemp.log</p> <p>rm $RESULTREPORT</p> <p>rm $RESULTTEMP</p> <p>while IFS=”:” read portnumber service</p> <p>do result=$( lsof -i:$portnumber | head -n2 > $RESULTTEMP)</p> <p>resultlength=$(cat “$RESULTTEMP” | wc -l )</p> <p>if [ “$resultlength” -gt “1” ] then</p> <p>#service is running there</p> <p>echo “OK: $service on $portnumber” >> $RESULTREPORT else</p> <p>echo “++++++ NOK: $service on $portnumber +++++++++” >> $RESULTREPORT</p> <p>fi</p> <p>done < $SERVICETESTS</p> <p>cat “$RESULTREPORT”</p></blockquote> <h4>checkservices-ALL.txt</h4> <blockquote><p>22:ssh<br/> 443:https<br/> 993:imaps<br/> 3306:mysql<br/> 389:ldap</p></blockquote> <h4>servers.list</h4> <p>This is your list of servers to process.</p> <blockquote><p>megatron:nomailq:nomaillog:diskdf:ALL<br/> magdelena:mailq:maillog:diskdf:ALL</p></blockquote> <p>In my crontab. I don’t want email noise from cron so I use /dev/null 2> &1 to null that.</p> <blockquote><p>30 08 * * * /usr/local/sbin/backup_app/checkservers.sh > /dev/null 2>&1</p></blockquote> <h3>Debugging</h3> <p>Debug email issues with functions-email.log</p> <p>For output issues log into your remote servers and run the check*.sh files to see what comes out.</p> <h3>Room for improvement</h3> <p>tmp files are used per server in the main loop, so take care not to run this script again until complete or you’ll get nonsense.</p> </div> </article> <article id="post-527" class="post-527 post type-post status-publish format-standard hentry category-uncategorized tag-assistive-technology tag-linux tag-tech-advice tag-windows"> <header class="entry-header"> <h2 class="entry-title"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/527-2/" rel="bookmark">Accessibility and Assistive Technology</a></h2> </header> <footer class="entry-footer"> <span class="posted-on"><span class="screen-reader-text">Posted on </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/527-2/" rel="bookmark"><time class="entry-date published" datetime="2017-08-22T07:29:23+00:00">August 22, 2017</time><time class="updated" datetime="2018-03-30T16:46:50+00:00">March 30, 2018</time></a></span><span class="byline"><span class="author vcard"><span class="screen-reader-text">Author </span><a class="url fn n" href="https://web.archive.org/web/20200514202132/https://comm-tech.org/author/alan/">Alan B.</a></span></span><span class="tags-links"><span class="screen-reader-text">Tags </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/assistive-technology/" rel="tag">assistive technology</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/linux/" rel="tag">linux</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/tech-advice/" rel="tag">tech advice</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/windows/" rel="tag">windows</a></span><span class="comments-link"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/527-2/#respond">Leave a comment</a></span> </footer> <div class="entry-content"> <h1>Computer Accesibility</h1> <h2>What is computer accesibility?</h2> <p>This term refers to the accessibility of a computer system to all people, regardless of disability or severity of impairment. It is largely a software concern; when software, hardware, or a combination of both, is used to enable use of a computer by a person with a disability or impairment, this is known as <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Assistive_Technology" target="_blank" rel="noopener">Assistive Technology</a>.</p> <p>For individuals with mild to medium vision impairment, it is helpful to use large <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Font" target="_blank" rel="noopener">fonts</a>, high <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Dots_per_inch" target="_blank" rel="noopener">DPI</a> displays, high-contrast themes and icons supplemented with auditory feedback and screen magnifying software.</p> <p>In the case of severe vision impairment such as blindness, <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Screen_reader" target="_blank" rel="noopener">screen reader</a> software that provides feedback via <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Text_to_speech" target="_blank" rel="noopener">text-to-speech</a> or a refreshable <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Braille_display" target="_blank" rel="noopener">braille display</a> is a necessary accommodation for interaction with a computer.</p> <h3>Assistive Technology Software</h3> <p><a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Vinux" target="_blank" rel="noopener"><b>Vinux</b></a> is a Linux distribution which has been specially designed for blind and partially sighted users.<br/> It is a remastered version of the Ubuntu distribution and provides users with two screen-readers, two full-screen magnifiers, global font-size and colour changing facilities. The system also supports USB braille displays.<br/> It can be run from a Live CD without making any changes to your hard drive</p> <h4>Requirements for Vinux main Edition:</h4> <ul> <li>1 GHz x86 processor.</li> <li>1 Gb of system memory (RAM).</li> <li>15 GB of hard-drive space (although this can be split onto 2 drives, a 5Gb / and a 10Gb /home partition fairly easily).</li> <li>Graphics card and monitor capable of 1024 by 768 resolution.</li> <li>Either a Cd/Dvd-drive or a Usb socket (or both).</li> <li>Internet access is helpful though not vital.</li> </ul> <h4>Requirements for Vinux (CLI) Installation:</h4> <ul> <li>300 MHz x86 processor.</li> <li>128 MiB of system memory (RAM).</li> <li>1 GB of disk space.</li> <li>Graphics card and monitor capable of 640×480.</li> <li>CD-ROM drive.</li> </ul> <h3>Some other free alternatives:</h3> <p><a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Orca_%28assistive_technology%29" target="_blank" rel="noopener"><b>Orca</b></a> is a free, open source, flexible, and extensible screen reader for Linux that provides access to graphical desktop environments via user-customizable combinations of speech, braille, and magnification.</p> <p>There are no specific system requirements, as it is expected to work even with very little RAM.</p> <p><a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/NonVisual_Desktop_Access" target="_blank" rel="noopener"><b>NVDA(NonVisual Desktop Access)</b></a> is a free, open source, portable screen reader for Microsoft Windows.</p> <p>NVDA uses <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/ESpeak" target="_blank" rel="noopener">eSpeak</a> as its integrated <a target="_blank" rel="noopener">speech synthesizer</a>, and also supports <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Microsoft_Speech_API" target="_blank" rel="noopener">SAPI</a> synthesizers. Output to braille displays is supported too.<br/> It runs on both 32-bit and 64-bit editions of Microsoft Windows XP or later.</p> <p>It has no additional hardware requirements beyond those of the operating system and requires less than 50 mb of disk space.</p> <h3>Proprietary software alternatives:</h3> <p>Proprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.</p> <p><a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/JAWS_%28screen_reader%29" target="_blank" rel="noopener"><b>JAWS (Job Access With Speech)</b></a> is a computer screen reader program for Microsoft Windows that allows blind and visually impaired users to read the screen either with a text-to-speech output or a <a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Refreshable_Braille_display" target="_blank" rel="noopener">refreshable braille display</a>.</p> <p>There are two versions of the program,standard and professional. A third version for MS-DOS is free.</p> <p><a href="https://web.archive.org/web/20200514202132/http://en.wikipedia.org/wiki/Window-eyes" target="_blank" rel="noopener"><b>Window-eyes</b></a> is a screen reader for Microsoft Windows, compatible with the following versions: Windows 2000, Windows XP, Windows Vista and Windows 7.</p> </div> </article> <article id="post-326" class="post-326 post type-post status-publish format-standard hentry category-uncategorized tag-how-to tag-linux tag-security tag-tech-advice"> <header class="entry-header"> <h2 class="entry-title"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/master-ssh-keys/" rel="bookmark">master ssh keys</a></h2> </header> <footer class="entry-footer"> <span class="posted-on"><span class="screen-reader-text">Posted on </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/master-ssh-keys/" rel="bookmark"><time class="entry-date published" datetime="2017-08-08T09:49:40+00:00">August 8, 2017</time><time class="updated" datetime="2019-02-11T14:04:05+00:00">February 11, 2019</time></a></span><span class="byline"><span class="author vcard"><span class="screen-reader-text">Author </span><a class="url fn n" href="https://web.archive.org/web/20200514202132/https://comm-tech.org/author/alan/">Alan B.</a></span></span><span class="tags-links"><span class="screen-reader-text">Tags </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/how-to/" rel="tag">how-to</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/linux/" rel="tag">linux</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/security/" rel="tag">security</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/tech-advice/" rel="tag">tech advice</a></span><span class="comments-link"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/master-ssh-keys/#respond">Leave a comment</a></span> </footer> <div class="entry-content"> <h1>Use ssh to run scripts on remote servers without entering a password.</h1> <h4>Create your ssh key</h4> <hr/> <p><code>ssh-keygen -b 4096 -t rsa -f ~/.ssh/keyname.rsa</code></p> <hr/> <p>will produce a keypair. The .rsa file will be the private and the .rsa.pub is the one that goes into authorized_keys on the remote server. If you don’t enter a password the key can be used with no user interaction. Do this when you need script operations on a remote server.</p> <h4>Load a key</h4> <hr/> <p><code> ssh-add keyname</code></p> <hr/> <h4>Upload your ssh key to a server</h4> <hr/> <p><code> ssh-copy-id -i keyname.rsa.pub username@remotehost</code></p> <hr/> <h4>Carry your key with your ssh session</h4> <p>if you need to carry your key somewhere, for instance if you will be chaining through to a host WITHIN the network of your remotehost and there is no direct ssh port forwarded to that host.</p> <hr/> <p><code>ssh -v username@remote -A</code></p> <hr/> <p>using -v (verbose) can help diagnose connectivity issues</p> <h4>Display the ssh keys you have loaded</h4> <hr/> <p><code>ssh-add -l</code></p> <hr/> <p>if you forgot to carry a key or you need to add a local key you will get the error:</p> <hr/> <p><code>ssh-add -l<br/> Could not open a connection to your authentication agent.</code></p> <hr/> <p>in this case use</p> <hr/> <p><code> ssh-agent bash<br/> ssh-add keyname</code></p> <hr/> <h4>Using alternative ports</h4> <p>Sometimes your remote host is running ssh on another port since 22 on that IP is already used. To reduce brute force attacks on the standard ssh port you can also use alternative ports by setting up the listening port in sshd_config on the server.</p> <p>Use the -p flag to specify:</p> <hr/> <p><code> ssh -p 41843 user@remotehost </code></p> <hr/> <p>You can use an -i flag to specify a key to use (always needed in bash scripting for using ssh password-less)</p> <hr/> <p><code> ssh -p 41843 -i ~/.ssh/keyfile.rsa user@remotehost </code></p> <hr/> <p>If you manage many servers you may want to use ~/.ssh/config to alias the connections.</p> <hr/> <p><code> vim ~/.ssh/config<br/> Host remotehost<br/> IdentityFile ~/.ssh/keyname.rsa<br/> Port 41843<br/> ServerAliveInterval 240</code></p> <hr/> <p>In the case above you can simply use ssh user@remotehost to get in using keyfile.rsa on port 41843</p> </div> </article> <article id="post-263" class="post-263 post type-post status-publish format-standard hentry category-uncategorized tag-how-to tag-linux tag-office-programs tag-tech-advice"> <header class="entry-header"> <h2 class="entry-title"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/forwarding-emails-in-zarafa-webapp/" rel="bookmark">How to forward email in Zarafa WebApp</a></h2> </header> <footer class="entry-footer"> <span class="posted-on"><span class="screen-reader-text">Posted on </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/forwarding-emails-in-zarafa-webapp/" rel="bookmark"><time class="entry-date published" datetime="2017-08-07T12:30:46+00:00">August 7, 2017</time><time class="updated" datetime="2018-03-30T16:47:39+00:00">March 30, 2018</time></a></span><span class="byline"><span class="author vcard"><span class="screen-reader-text">Author </span><a class="url fn n" href="https://web.archive.org/web/20200514202132/https://comm-tech.org/author/maria/">Maria S.</a></span></span><span class="tags-links"><span class="screen-reader-text">Tags </span><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/how-to/" rel="tag">how-to</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/linux/" rel="tag">linux</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/office-programs/" rel="tag">office programs</a>, <a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/ABOUT/tech-advice/" rel="tag">tech advice</a></span><span class="comments-link"><a href="https://web.archive.org/web/20200514202132/https://comm-tech.org/forwarding-emails-in-zarafa-webapp/#respond">Leave a comment</a></span> </footer> <div class="entry-content"> <p>1. Click <strong>Setting</strong> top-right.</p> <p>2. Click <strong>Mail Filters </strong>to the left.</p> <p><a href="https://web.archive.org/web/20200514202132/http://comm-tech.org/screenshots/1.png" target="_blank" rel="noopener"><img class="alignnone wp-image-264" src="https://web.archive.org/web/20200514202132im_/https://comm-tech.org/wp-content/uploads/2017/08/Screen-Shot-2017-08-07-at-13.20.35-300x161.png" alt="" width="313" height="168"/></a></p> <p>3. Create a rule. When the message is sent to … you (choose your name) and click the <strong>To:</strong> button in the Address Book</p> <p>4. Do the following… Forward the message to… either choose from Address Book and click <strong>To:</strong> or enter external address in <strong>To:</strong> field</p> <p>5. Tick <strong>Stop processing more rules</strong></p> <p>6. 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