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To: root@chaos.analogic.com
cc: Andrea Arcangeli <andrea@suse.de>,
        "Jeff V. Merkey" <jmerkey@timpanogas.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [Fwd: sendmail fails to deliver mail with attachments in /var/spool/mqueue] 
In-Reply-To: Message from "Richard B. Johnson" <root@chaos.analogic.com> 
   of "Fri, 10 Nov 2000 15:07:46 CDT." <Pine.LNX.3.95.1001110150021.5941A-100000@chaos.analogic.com> 
Date: Sat, 11 Nov 2000 22:39:02 -0300
From: Horst von Brand <vonbrand@sleipnir.valparaiso.cl>
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"Richard B. Johnson" <root@chaos.analogic.com> said:
> On Fri, 10 Nov 2000, Andrea Arcangeli wrote:

[...]

> > Ok. So please now show a tcpdump trace during the `sendmail -q` so we
> > can see what's going wrong in the TCP connection to the smtp server:
> >
> > 	tcpdump port smtp

> I tried to send Jeff a 45 Megabyte file. It is still in the queue.

[...]

> It isn't a TCP/IP stack problem. It may be a memory problem. Every time
> sendmail spawns a child to send the file data, it crashes.  That's
> why the file never gets sent!

In my experience, if you try to send large messages over unreliable
networks (we sometimes see 50 or more % losses due to chronical link
overload downstream) the connection breaks up and the messages take a long
time to get out of the door. No, not just Linux; our SunOS/Solaris/Linux
mail servers have all shown the same behaviour. Makes sense: Unless the
message is sent and ACKed, it stays put. SMTP has no "resume message" AFAIK...
This could also be an explanation for this phenomemnon.
--
Horst von Brand                             vonbrand@sleipnir.valparaiso.cl
Casilla 9G, Vin~a del Mar, Chile                               +56 32 672616
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