For the AsteriskNOW box we are using as our main Internet gateway we needed to support automatic updating via dyndns.org. The solution was ddclient found at sourceforge.
After downloading the tgz file and unpacking into a temp folder with tar -xzvf ddclient*, the README file included contains good instruction for installing.
You will need to edit the /etc/ddclient/ddclient.conf file. In our case, we configured using:
daemon=300 # check every 300 seconds syslog=yes # log update msgs to syslog mail=root # mail all msgs to root mail-failure=root # mail failed update msgs to root pid=/var/run/ddclient.pid # record PID in file. ssl=yes # use ssl-support. Works with ssl-library # postscript=script # run script after updating. The new IP is added as argument. # use=if, if=ppp0 # login=username # default login password=password # default password #mx=mx.for.your.host # default MX #backupmx=yes|no # host is primary MX? #wildcard=yes|no # add wildcard CNAME? # server=members.dyndns.org, \ protocol=dyndns2 \ somewhere.mine.nu