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List:       bugtraq
Subject:    Re: BoS: Someone reminded me of something today ;)
From:       Rick Weldon <rick () wisetech ! com>
Date:       1996-10-30 22:10:38
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On Wed, 30 Oct 1996, Alan Cox wrote:

> Now that various people have put bits of info in the public domain[1]
> so nobody
> at 3com can claim I'm breaking confidences, I'd like to invite the
> entire
> world to try sending IP data with 0 length options (IP or TCP) to the
> management port of all their 3com routers and kit, especially the little
> routers, bridges and managed hubs.
>
> Have fun
>
> Alan
> [1] Like the ip_send documentation.
>
>

They will of course barf depending on which rev of the software is on the
device. I have run into this with older equipment, especially comm
servers like the CS2600. I never thought of it as breaking a confidence
to say that if you turn IP options on and try to talk through a 2600 it
will spontaneously reboot or hang. I thought this was a well know problem.

>From the FreeBSD /etc/sysconfig file:

#
# Some broken implementations can't handle the RFC 1323 and RFC 1644
# TCP options.  If TCP connections randomly hang, try disabling this,
# and bug the vendor of the losing equipment.
#
tcp_extensions=NO


I suspect that more than just the comm servers suffer from this problem,
although I don't know which ones.

Rick

| Rick Weldon -- WISE-Tech LLC
| E-mail: rick@wisetech.com

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