From owner-freebsd-hackers  Thu May  8 13:27:04 1997
Return-Path: <owner-hackers>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.5/8.8.5) id NAA17451
          for hackers-outgoing; Thu, 8 May 1997 13:27:04 -0700 (PDT)
Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.50])
          by hub.freebsd.org (8.8.5/8.8.5) with SMTP id NAA17446
          for <freebsd-hackers@FreeBSD.ORG>; Thu, 8 May 1997 13:27:01 -0700 (PDT)
Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id NAA25464; Thu, 8 May 1997 13:20:01 -0700
From: Terry Lambert <terry@lambert.org>
Message-Id: <199705082020.NAA25464@phaeton.artisoft.com>
Subject: Re: FTP Performance
To: fenner@parc.xerox.com (Bill Fenner)
Date: Thu, 8 May 1997 13:20:01 -0700 (MST)
Cc: tom@sdf.com, fenner@parc.xerox.com, smc@servtech.com,
        danny@panda.hilink.com.au, freebsd-hackers@FreeBSD.ORG
In-Reply-To: <97May8.111829pdt.177486@crevenia.parc.xerox.com> from "Bill Fenner" at May 8, 97 11:18:22 am
X-Mailer: ELM [version 2.4 PL24]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: owner-hackers@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

> Tom Samplonius <tom@sdf.com> wrote:
> >  How would this misconfiguration occur?  Just two routers with
> >mis-matched MTU/MRU sizes?
> 
> No, the only way for PMTU discovery to fail is for a router to not
> return ICMP fragmentation required errors.  I don't know how to
> configure a router to do this, since it's required by RFC1812,
> but perhaps there's a firewall in the way.

Or a proxy server.  It's impossible to legally proxy this as anything
but unicast boradcasts, and it requires a *very* smart proxy, then,
and it's still not RFC compilant.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.