Unable to reverse lookup 1 PTR from a zone?

[James K. McConnell]

> >It appears to me that I have one of two problems.  First, the 8.1.2
> >resolver may have a bug, and I should upgrade it to 8.2.2p5.  I plan to
> >do this, but I'd prefer to track down this problem first.  Second, it
> >may be possible that the response never makes it back to the host
> >that is requesting information.  I've strace'd the nslookup, and it
> >simply tells me I'm getting a timeout.  When I dumpdb on the server,
> >I can clearly see this record is loaded, and I receive a response for
> >this record from every other host I've tried.
> 
> And the log messages show the server is sending the response.
> 
> >What can I do to track down this problem?  Why should this affect only
> >one record?  Any assistance is appreciated.  I can provide any 
> information
> >that may be necessary to track down this problem.
> 
> Have you used tcpdump on the client to see whether the response packet is
> being received.
> 
> It could be a network hardware problem, being tickled by the particular
> pattern of bytes in this response.

After testing this with tcpdump, I've found the following:

Looking up 192.168.21.2 while using tcpdump has no problem at all.

Looking up 192.168.21.2 while *not* using tcpdump yields the same problem
I've seen all along.  

Since I appear to only have the problem when tcpdump isn't running, I 
tried a capture from another machine.  The response from bind is being
sent correctly , that much is clear.  It's not the fault of bind, perhaps 
there is something flaky with the machine sending the query.  At any rate,
now I know I don't have a bind problem...

Thanks!

Jim McConnell