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From: George Neville-Neil <gnn@freebsd.org>
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To: Doug Barton <dougb@FreeBSD.org>
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Cc: Navdeep Parhar <np@FreeBSD.org>, net@freebsd.org
Subject: Re: Interface MTU question...
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On Jul 12, 2012, at 14:28 , Doug Barton wrote:

> While y'all are looking at MTU (which is an increasingly important topic
> as we move into a Gig+ world) I'm wondering what our support is for
> https://tools.ietf.org/html/rfc4821 ?? I asked this a while back and
> never got an answer.
> 
> This method of PMTUD is really important given the massive (stupid)
> brokenness of people routinely blocking all of ICMPv4.

We do not support that RFC and support in other OSs is quite limited.
It does not seem to be have been taken up by the Internet community
in general.

That being said, it is an interesting mechanism.  Probably not a bad idea
for a wish list item.

Best,
George