[CentOS] OT: good free DNS tools?

Hey guys and gals,

Anyone know of a half decent tool like DNSstuff.com only free?

I need to run some diag on a few domains but it is basically a 1 shot
deal and hard to justify buying.

thanks,
-Alan

-- 
“Don't eat anything you've ever seen advertised on TV”
         - Michael Pollan, author of "In Defense of Food"