Subject: Re: lamer mtu question.
To: Herb Peyerl <firstname.lastname@example.org>
From: Manuel Bouyer <email@example.com>
Date: 07/23/2001 11:40:49
On Mon, Jul 23, 2001 at 12:42:14AM +0200, Herb Peyerl wrote:
> Manuel Bouyer <firstname.lastname@example.org> wrote:
> > > Initially I used an mtu of '296' and started seeing the problem. So I
> > > bumped it down to 250 out of curiosity ...
> > >
> > > Later I bumped the mtu up to '502' (some random number higher than 250)
> > > and it all works fine.
> > >
> > > So what am I missing? Shouldn't this all be independant of the mtu/mru?
> > > Or is there some sysctl I'm missing?
> > Maybe it's just that the other (ppp) end doesn't propely fragment big packets ?
> The other end is a DMS-500 phone switch that I have no control of.
> > Did you try to turn on path MTU discovery on both host ?
> > sysctl -w net.inet.ip.mtudisc=1
> you mean my jornada running pppd and the 20 hop away machine with
> sshd? or you mean both ends of the ppp connection?
No, both end of the ssh connection. If the DMS-500 fails to fragment
pakets, maybe at last it properly returns an ICMP need-frag for such
Manuel Bouyer, LIP6, Universite Paris VI. Manuel.Bouyer@lip6.fr