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

bert hubert bert.hubert at netherlabs.nl
Fri Mar 24 19:39:26 UTC 2006

On Fri, Mar 24, 2006 at 02:15:54PM -0500, Tony Adams wrote:
> C:\dig>dig earthlink.net mx @ns2
> ;; Truncated, retrying in TCP mode.    <<<<  See what I mean?

Can you show the exact and full output of the same question sent to the
verizon servers?

> 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?

What probably happens is that the verizon servers internally remove all
additional records that would end up beyond 512 bytes. 

In other words, the omit all records that are optional and make their answer
fit in 512 bytes.

If you show the output of the verizon servers, I can confirm and perhaps
implement this behaviour in 2.9.21.

Thanks for the report!

http://www.PowerDNS.com      Open source, database driven DNS Software 
http://netherlabs.nl              Open and Closed source services

More information about the Pdns-users mailing list