[Pdns-users] Host looks causing issues

[Tony Adams]

There was a fix to the way that the PowerDNS recursor returns UDP
replies.  The fix changed the behavior of the recursor so that it would
return as much information as it could in a single UDP packet, this
should be sufficient for nearly all applications (read, I can't think of
a situation where it would be a problem).  Initially if a domain
administrator configured a very large number of MX records for their
domain (earthlink was where I ran into the issue) then reply would be
too large to send in a UDP packet.  The reply would be truncated and you
get the behavior that you're seeing.  You can work around this by
allowing your recursor to answer TCP queries, or upgrade to a later
version of the PowerDNS recursor that includes the fix.

Tony Adams
Sr. Systems Engineer
E Solutions Corporation
> -----Original Message-----
> From: pdns-users-bounces at mailman.powerdns.com [mailto:pdns-users-
> bounces at mailman.powerdns.com] On Behalf Of John Williams
> Sent: Tuesday, August 15, 2006 2:22 PM
> To: pdns-users at mailman.powerdns.com
> Subject: [Pdns-users] Host looks causing issues
> 
> I've encountered a problem that seems to have been caused by PDNS.
> A number of emails being sent are failing after retries this is
because
> the
> MX lookups are having issues.
> For instance:
> 
> 
> # host -t mx tiscali.co.uk
> ;; Warning: Message parser reports malformed message packet.
> ;; Truncated, retrying in TCP mode.
> ;; connection timed out; no servers could be reached
> 
> 
> I know the MX records exist since I can do an MX lookup on another
server
> not using our PDNS server to do the lookup via.
> Any ideas how I can get around this issue?
> 
> We are running version 2.9.18
> 
> 
> Thanks
> John
> 
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> 
> 
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