Subject: Re: gsip sends byte-swapped vlan tags
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Manuel Bouyer <>
List: tech-net
Date: 01/26/2006 20:40:36
On Thu, Jan 26, 2006 at 11:13:04AM -0500, der Mouse wrote:
> >>> Bugs have to be fixed, not worked around by disabling a feature.
> >> I agree.  But then why do we support MSS clamping?
> > Because we cannot make Verizon stop using pppoe :-)
> PPPoE is not the problem either; it merely is the commonest cause of
> setups which expose the problem.  Making Verizon stop using PPPoE would
> just be another workaround.
> The real problem is on the other end: hosts which try to do PMTU-D, but
> are behind boxes (usually misconfigured firewalls) which drop the ICMPs
> necessary for PMTU-D to function.

Not only, some PPPoE setup just won't send the ICMP unreachable message,
because the equipement at which the MTU is lowered doesn't appear at the
IP level.

Manuel Bouyer <>
     NetBSD: 26 ans d'experience feront toujours la difference