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To: Tom Samplonius <tom@sdf.com>
cc: Bill Fenner <fenner@parc.xerox.com>, Shawn Carey <smc@servtech.com>,
        "Daniel O'Callaghan" <danny@panda.hilink.com.au>,
        freebsd-hackers@freebsd.org
Subject: Re: FTP Performance 
In-reply-to: Your message of "Wed, 07 May 97 23:58:38 PDT."
             <Pine.NEB.3.94.970507235728.29271B-100000@misery.sdf.com> 
Date: Thu, 8 May 1997 11:18:22 PDT
From: Bill Fenner <fenner@parc.xerox.com>
Message-Id: <97May8.111829pdt.177486@crevenia.parc.xerox.com>
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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.

  Bill