OT: validating DNS

[Derek Broughton]

Can anybody recommend _free_ tools for validating my DNS?

While checking that my ISP had finally (much too late, imo) applied the
patches for the DNS vulnerability Dan Kaminsky found (and if you run a
business, or are just reasonably paranoid, and don't know what I'm talking
about, run to http://www.doxpara.com), I ended up at dnsstuff.com, which
reports "critical" errors for my domain.  I have my doubts - though I
confess there are some oddities - but I'll be damned if I'm giving them a
credit card number to see their report.

Nothing else I've checked sees errors at all, let alone critical ones.
-- 
derek