DNS lookups gone on coffee break

[Shawn L Johnston]

I've been seeing a few weird dns problems on my network over the last
few weeks. A couple of sites won't resolve: www.opengl.org,
linuxworld.com, and a few others. I know that these sites are up and
running because if I access them through a different network or if I use
a DNS server that is on another network I can resolve them.

Trying an nslookup on www.opengl.org through my dns servers results in a
connection time out. However if I do an nslookup on www.opengl.org's ip
address (192.48.159.181) through my dns servers I recieve a response 

Non-authoritative answer:
181.159.48.192.in-addr.arpa     name = www.opengl.org.

We switched our T-1 provider about a month ago and I suspect that I
haven't configured something correctly when I changed the ip addresses
for the DNS servers. 


The weird thing is most external sites reslove without any problems.
Because I'm starting to notice it now though (as opposed to when I
switched the network) I think the problem is gradually getting worse.

I'm running bind 9.2 on linux. I've enabled the querylog feature but I
haven't seen any information in the logs thats helped me figure out
whats going on. I'm not running any caching server.

Any thoughts, suggestions?

Thanks,

Shawn