Re: [Exim] SMTP data timeout - troubleshooting tips??

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Author: exim-users-admin
Date:  
To: Michael Coxe
CC: exim-users
Subject: Re: [Exim] SMTP data timeout - troubleshooting tips??
Hi,

On Wed, Sep 24, 2003 at 04:24:02PM -0700, Michael Coxe wrote:
> I've searched the Exim archives & Usenet regarding an Exim error
> message when certain hosts attempt delivery to my mailserver.
> For example (the namedroppers mailing list):
>
> SMTP data timeout (message abandoned) on connection from psg.com [147.28.0.62]
>
> The concensus is that the error is genaerally caused by a firewall
> or other such device. In may case (home environment), it might be
> my DSL box/firewall, a ZyXEL model Prestige 643.


You could try to disable path mtu discovery[1] on the mailserver
and see if this fixes your problem. If it does, try to find the broken
or misconfigured router/firewall that swallows the ICMP-unreachable
packets. Increasing timeouts will *not* work around
the problem because the (overly big) packets are never received by
one of the hosts.

        Chris



[1]:
        Linux: echo 1 >/proc/sys/net/ipv4/ip_no_pmtu_disc
        BSD/Cisco/...: http://www.netheaven.com/pmtu.html


--
Christian Vogel -- chris@???