Subject: Obscure MTU problem
To: Apache Mailing List <new-httpd@hyperreal.com>
Date: Mon, 25 Mar 1996 23:30:53 +0000 (GMT)
From: Ben Laurie <ben@gonzo.ben.algroup.co.uk>
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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?

Cheers,

Ben.

-- 
Ben Laurie                  Phone: +44 (181) 994 6435
Freelance Consultant and    Fax:   +44 (181) 994 6472
Technical Director          Email: ben@algroup.co.uk
A.L. Digital Ltd,           URL: http://www.algroup.co.uk
London, England.