Author: Jakob Hirsch Date: To: exim-users Subject: Re: [exim] An interesting problem (apparent duplicate delivery)
Tom Kistner wrote:
> Do you use AV or spam scanning after DATA? If yes, the cause may be a
> post-data timeout on the sending host. Exim may then send his 220 to a
> dead channel and queue the message, while the sending host has timed out
> the SMTP session and will retry sending the message later.
I saw this happening with a too-tight firewall. After upgrading to
spamassassin 3.1 I had suddenly scantimes above 60s. In the meantime, the
firewall (of the sending host) considered the connection as timed out, so
the 250 from my Exim didn't get through and the sending MTA tried again
and again.
