Anyone know why this happens?

[Mike Kercher]

Excellent info...thanks a lot :)

Mike


-----Original Message-----
From: MailScanner mailing list [mailto:MAILSCANNER at JISCMAIL.AC.UK] On Behalf
Of Jeff A. Earickson
Sent: Saturday, May 03, 2003 6:27 AM
To: MAILSCANNER at JISCMAIL.AC.UK
Subject: Re: Anyone know why this happens?


Hi,
   The remote side is whacking the connection before the data transfer
completes.  This is not a DNS issue, because the DNS lookup are already done
and the connection has been made by this point.  I ran into this with
another site using Novell Groupwise email and some firewall setup I've never
heard of.  The problem was at their end. They discovered that the MTU
setting on their firewall was smaller than their MTU on their network.  As
packets went out thru the firewall, they were fragmented.  All that packet
fragmentation and reassembly slowed the connection to a crawl.  In general,
most mail software has timeout settings (sendmail has a lot of them, see the
Bat book), and if a crawly data connection takes longer than one of these
timeout settings, then the mail software thinks the connection is dead and
whacks it.

If you are seeing the EOM message in your logs, then the problem is at the
remote end.  Either their mailer timeouts are way too small (mailer
misconfigured), their network connection is way slow (eg, fragmented
packets), or their firewall is screwing up the connection. Since firewall
boxes are the new thing, I always ask remote sites to check the config on
them first.

--- Jeff Earickson

On Fri, 2 May 2003, Mike Kercher wrote:

> Date: Fri, 2 May 2003 13:57:01 -0500
> From: Mike Kercher <mike at CAMAROSS.NET>
> Reply-To: MailScanner mailing list <MAILSCANNER at JISCMAIL.AC.UK>
> To: MAILSCANNER at JISCMAIL.AC.UK
> Subject: Anyone know why this happens?
>
> May  2 13:57:48 genesis sendmail[27561]: h42IoYo27561: collect: 
> premature EOM: Error 0 May  2 13:57:48 genesis sendmail[27561]: 
> h42IoYo27561: collect: unexpected close on connection from 
> mxsmta01.inithost.com, sender=<trudy at dschmich.com>: Error 0
>
> Is this due to a DNS timeout or something?
>
> Mike
>