Editing dynamic-dns

=Creating a dynamic DNS entry in your DNS== This page details how to create a dynamic dns host entry for a system that is behind a fire-walled cable modem or other such network connection that has a public IP address that changes from time to time (more than hourly). This example has been implemented on a Solaris system behind the firewall, and a BIND 9 system running on a name server on the Internet. References have been generalized for host.domain.ca. If you use this example, replace these examples with your hostname. ==TSIG Transaction Signatures=== You need to have bind and the bind utilities installed (greater than Bind 8). ===On the client side:=== #> mkdir /etc/ddns #> cd /etc/ddns #> /opt/csw/sbin/dnssec-keygen -a HMAC-MD5 -b 128 -n HOST host.domain.ca. Transfer the public key to the public DNS server ===On the server side=== * Add keys to directory #> mkdir /var/named/keys #> $EDITOR /etc/named.conf Add the following to named.conf on the bind server: // - Include keys.conf for dynamic dns include "keys.conf"; and to the domain entry: allow-update { key host.domain.ca.; }; * create the keys.conf config file on the bind server (master). #> vi /var/named/keys.conf key host.domain.ca. { algorithm hmac-md5; secret "blahblahblah"; }; HUP named ===On the client side:=== Run the nsupdate command from the client client-root-#nsupdate -k /etc/ddns/Khost.domain.ca.+157+55549.private > update delete host.domain.ca IN A > update add host.domain.ca. 600 IN A nnn.nnn.nnn.nnn > send > quit Alternative one line command /opt/csw/bin/nsupdate -k /etc/ddns/Khost.domain.ca.+157+55549.private -d /etc/nsupdate /etc/nsupdate contains the update commands to be sent with the new public address. == Automating for hosts behind a firewall with a public address == Update Script <pre> #!/bin/sh TEMPFILE=/tmp/dyndns.cmd OLDIP_FILE=/var/tmp/dyndns.myip KEYFILE=/etc/ddns/Khost.domain.ca.+123+45678.private OLDIP=`/bin/cat ${OLDIP_FILE}` NEWIP=`/opt/csw/bin/wget -q -O- http://whatismyip.org/` echo old is $OLDIP, new is $NEWIP if [ "$OLDIP" = "$NEWIP" ] ; then echo IP is the same exit 0 fi # else - update it echo update delete host.domain.ca IN A > $TEMPFILE echo update add host.domain.ca 600 IN A $NEWIP >> $TEMPFILE echo >> $TEMPFILE /opt/csw/bin/nsupdate \ -k ${KEYFILE} \ -d $TEMPFILE # hopefully that gives us a good exit status if [ $? = 0 ] ; then echo $NEWIP > $OLDIP_FILE exit 0 fi </pre> =References= * http://caunter.ca/nsupdate.txt * http://www.oceanwave.com/technical-resources/unix-admin/nsupdate.html * http://fengnet.com/book/DNS.and.BIND.5th.Edition/dns5-CHP-11-SECT-1.html * http://linux.yyz.us/nsupdate/ * http://linux.yyz.us/dns/ddns-server.html

Summary:

This change is a minor edit.

Username: