Hello,
we recently had some situation of full bandwidth usage through our firewall,
and by investigation we discovered that this was caused by a specific mail to a
specific destination sent via Postifx 3.1.6.
We found an ACK SYN DUP flood during the problem, many many packets sent, and
this on the postfix log regarding that transaction:
enabling PIX workarounds: disable_esmtp delay_dotcrlf for...
conversation with ... timed out while sending message body
We had to block that destination on the firewall and remove the message on the
queue, or it would restart the problem when retried by the queue.
The same mail sent via Postfix 2.7.1 on a different data center with the same
firewall was sent without problems and without the postfix logs above.
I can reproduce the problem by sending again the same email.
Other different smaller mails to the same desintation are sent correctly.
What may be happening?
Gabriele
Sonicle S.r.l.
:
http://www.sonicle.com
Music:
http://www.gabrielebulfon.com
Quantum Mechanics :
http://www.cdbaby.com/cd/gabrielebulfon
