[Pdns-users] greater number of truncated replies with pdns_recursor?

Alan Hodgson ahodgson at simkin.ca
Fri Mar 24 19:37:24 UTC 2006

On March 24, 2006 11:15 am, "Tony Adams" <aadams at esnet.com> wrote:
> This 'truncated' reply causes MS SMTP (IIS/Exchange) to retry the
> request in TCP mode.  Now that I'm allowing TCP connections to my DNS
> servers the behavior should cease.  I guess my question becomes, why
> does the pdns recursor seem to produce more truncated replies than the
> (presumably) bind server run by verizon ( to whom I was sending
> recursive requests before I upgraded to pdns 2.9.20?

precursor seems to return all the A records for the MX servers in the 
ADDITIONAL section, which is afak permitted, but does result in the result 
packet exceeded 512 bytes and requiring TCP.

I notice that dnscache does not do this, although it does receive and cache 
the A records for future retrieval.   I don't have a BIND server handy to 
try, but I would assume that your other recursor probably doesn't return 
the A records when answering the recursive MX query.

"The best we can hope for concerning the people at large is that they
be properly armed." -- Alexander Hamilton

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