Still Having Intermittent Issues Resovling External Domains

[Ronan Flood]

Joel M Nimety <jnimety at cybergnostic.com> wrote:

> >>tcpdumps during the outages show recursive requests going out but no
> >>replies coming back.

You shouldn't be seeing *recursive* queries going out unless you're
using forwarding, which from your config you are not.

Your earlier tcpdump sample:

> 08:20:46.981003 ns79.cybergnostic.com.32817 >
> ns77.cybergnostic.com.domain:  229 00+ A? cnn.com. (25) (DF)
> 08:20:51.984474 ns79.cybergnostic.com.32817 >
> ns77.cybergnostic.com.domain:  229 00+ A? cnn.com. (25) (DF)
> 08:21:16.990741 ns77.cybergnostic.com.domain >
> ns79.cybergnostic.com.32817:  229 00 ServFail 0/0/0 (25) (DF)

shows recursive queries from your ns79 to your ns77, but doesn't
show any queries going out from ns77.  What's happening in that
30 seconds between 20:46 and 21:16?  Are you running tcpdump in
the right way, and in the right place, to pick up traffic from
ns77 to port 53 on external servers, and any responses back?

-- 
                      Ronan Flood <R.Flood at noc.ulcc.ac.uk>
                        working for but not speaking for
             Network Services, University of London Computer Centre
     (which means: don't bother ULCC if I've said something you don't like)