If you have to do anything with DNS I strongly suggest taking a look at PowerDNS. This open source DNS server rocks. The authors are on top of all of the issues around DNS, patch as soon as necessary and in general just make the thing stable. The real beauty though is when you combine PowerDNS with PostgreSQL and throw in a dash of Ruby for kicks. With this combination you get a simple means for adding and modifying records on the fly along with support for DNS configurations that aren’t even possible with a static DNS server.

PostgreSQL will handle all of your simple, standard DNS records and Ruby can be used to handle more esoteric things like wildcard matches for DNS resolution and other nifty things. PowerDNS will cache your queries avoiding the need to go to the database for every request and you can easily throw new records into the database and server will respond instantly without needing to reload zone files and the like. Highly configurable and elegant!