I had to update several reverse zone files today, so wrote a quick for-loop in bash to freeze and thaw all the zones. The script parsed the zone file names and reversed them into a proper d.c.b.a.in-addr.arpa format. Later I tweaked it with sed to make it more flexible (in order to pass it a full or partial IP address), but ended up using tac for the reversing part instead – that’s what it’s made for after all. And if you’re wondering what tac stand for, just read cat backwards. :-)
Surnia Ulula
UNIX Ideas for SysAdmins
Quick Freeze / Thaw of Reverse Zones
Update a Dynamic DNS IP with BIND
I wrote the following nsupdate-ddns.sh script to update the dynamic DNS entry for my laptop when switching network locations. There are several ways to execute a script like this automatically (cronjob, startup script, launcher, etc.) — I chose to use Sidekick for Mac OS X, which allows me to execute it when switching locations (either network or physical). This script can also create the private authentication key needed by the DDNS BIND server, and will display some sample configuration values. If you’re setting up a new DDNS BIND server, you can use the examples to configure your dynamic zone file.



