zaylea's blog

This is a script to automatically update your IP on SDF's mdns.org.
It saves the last IP you sent to mdns in local file and if the IP has changed
it will send the update. This script works even behind NAT. Run it as a cron
job to be "automatic".

It requires pexpect: http://pexpect.sourceforge.net
pexpect requires a POSIX operating system (i.e. not windows, but linux, Mac OS X, etc.)

Update: I didn't realize that SDF had a page to check your IP. It's at http://sdf.lonestar.org/ip/ (thanks randy).
You can change the IP_CHECK_URL to that and the script will still work because it just uses a regex to find an IP on the page.