Message-Id: <199603260011.SAA18842@sierra.zyzzyva.com>
To: new-httpd@hyperreal.com
Subject: Re: Obscure MTU problem 
In-reply-to: ben's message of Mon, 25 Mar 1996 23:30:53 +0000.
         <9603252330.aa02562@gonzo.ben.algroup.co.uk>
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Date: Mon, 25 Mar 1996 18:11:32 -0600
From: Randy Terbush <randy@zyzzyva.com>
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Reply-To: new-httpd@hyperreal.com

> Hi,
> 
> I've just been investigating a problem with our new Apache based
> webserver where people using dialups with _some_ ISPs were having extreme
> difficulty with our site (intermittently). The symptom at their end was that
> they got connected but then hang indefinitely waiting for the data. At our end
> we see connections for the data sitting at FIN_WAIT_1 with lots of stuff in
> the send queue.
> 
> I seem to have solved this problem by setting the MTU to 512 (default 1500).
> SCO 5 is uses Path MTU Discovery (a lot of implementations use MTU=512 for all
> nonlocal nets) which is probably the cause of the problem. We don't have any
> such problem with a SCO 3 box and an SGI on the same net.
> 
> Any thoughts, anyone?

Are these clients MacTCP clients by chance? I understand that Path Discovery
on this TCP stack sucks.