Carver Banks wrote:
Hello Everyone,
I am seeing weird bounces on my postfix server and can't quite figure out why...
It looks like it is failing while passing the mail off to a spam appliance, but
from the spam appliance side I see no record of the message. Also
Any ideas, I have a couple examples below?
Example Mail.log entry:
Feb 12 06:17:53 mail01 postfix/smtp[24220]: C06165CE92:
to=<user.n...@domain.com>, relay=175.21.0.67[175.21.0.67]:2525, conn_use=18,
delay=16, delays=1.4/13/0/1.7, dsn=5.5.0, status=bounced (Protocol error: host
175.21.0.67[175.21.0.67] said: 250 2.0.0 Ok (in reply to DATA command))
The SMTP protocol has gotten out of sync. Often this is
caused by a poor PIPELINING implementation on the receiver.
You can disable postfix PIPELINING with
smtp_discard_ehlo_keywords or only for that destination using
smtp_discard_ehlo_keyword_address_maps
http://www.postfix.org/postconf.5.html#smtp_discard_ehlo_keywords
The above is really just a guess (although a pretty good one).
If it doesn't help or you want to definitely diagnose the
problem you'll need to post a packet capture to the list
covering a time period when the error occurs.
http://www.postfix.org/DEBUG_README.html#sniffer
-- Noel Jones
