A line of script to send you an email if your DHCP allocated IP address has changed.
Either run it from a cron or put it in /etc/rc.local
ls -rt /var/lib/dhcp/dhclient*eth0* | xargs grep fixed-address | tail -2 | awk ‘{print $3}’ | xargs echo -n | sed -e ‘s/;//g’ | awk ‘{if ($1 != $2) { print $2}}’ | mail me@example.org -E’set nonullbody’ -s “My new IP”