From owner-freebsd-net  Wed Aug  8 10:25:42 2001
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Date: Wed, 8 Aug 2001 10:25:33 -0700
From: Brooks Davis <brooks@one-eyed-alien.net>
To: Mike Tancsa <mike@sentex.net>
Cc: freebsd-net@FreeBSD.ORG
Subject: Re: gif MTU of 1280 ?
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On Wed, Aug 08, 2001 at 10:22:22AM -0400, Mike Tancsa wrote:
>=20
> Just wondering, is there a reason why the MTU of the gif interface defaul=
ts=20
> to 1280 ?  Why not 1500 ?

It can't be 1500 because the tunneling protocol is designed to use an
MTU which insures that packets don't get fragmented (except in one weird
edge case.)  Since there is a wrapping IP header, the MTU of an IP over
IP tunnel can be no more then 1480 in the common case.

-- Brooks

--=20
Any statement of the form "X is the one, true Y" is FALSE.
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