Intermittent DNS Problem

[WebIdentity]

Hi There

I had recently moved about 70 users to a new server, new dc, etc about 1 month ago.

Although it may seem that i had ironed out any config problems or issues that people may of had i'm still scratching my noggin about a particular issue.

Occasionally i receive this error in /var/log/messages during which time nobody else can resolve any of the domains binded to my server, you wait 5 mins the problem is magically fixed and i'm left wondering whats going on.

Apr 19 21:15:53 srv01 named[2972]: client 84.103.237.145#6882: error sending response: host unreachable
Apr 19 22:17:42 srv01 named[2972]: client 212.43.194.3#4668: error sending response: host unreachable
Apr 19 22:18:14 srv01 named[2972]: client 212.43.194.3#4668: error sending response: host unreachable
Apr 19 23:41:01 srv01 named[2972]: client 212.43.194.3#4668: error sending response: host unreachable
Apr 19 23:41:33 srv01 named[2972]: client 212.43.194.3#4668: error sending response: host unreachable
Apr 20 00:09:05 srv01 named[2972]: client 192.114.65.49#4670: error sending response: host unreachable

I have tried reconfiguring apf to follow the following firewall rules.

http://faq.cpanel.net/show.cgi?qa=108499296901804

And I have changed the /tmp directory permissions to 1777 as suggested in other fixes.

I have upcp'ed, fixnamed, fixeverything (pretty much) to no avail.

I have tested this issue by digging through other nameservers and on occasions i can get a SERVFAIL message, but nothing really conclusive to help me track down the problem.

If anyone has some suggestions i would be very open to trying a few things. Thanks very much.

Server Name is srv01.webidentity.com.au and a non-authoritive domain is webvantage.com.au

Cheers.

[WebIdentity]

Apr 20 01:04:21 srv01 named[2972]: client 212.43.194.3#4668: error sending response: host unreachable
Apr 20 01:04:54 srv01 last message repeated 33 times
Apr 20 01:04:54 srv01 named[2972]: client 212.43.194.3#4668: error sending response: host unreachable

This happened again (just then) and dns just died