Subject: Re: Stupid ICMP and fragmentation tricks
To: Ignatios Souvatzis , M Graff <firstname.lastname@example.org>
From: Ignatios Souvatzis <email@example.com>
Date: 09/21/1999 18:10:25
On Tue, Sep 21, 1999 at 06:07:39PM +0200, Ignatios Souvatzis wrote:
> On Tue, Sep 21, 1999 at 08:59:39AM -0700, M Graff wrote:
> > Bill Sommerfeld <firstname.lastname@example.org> writes:
> > > Blocking all ICMP's breaks *all* known Path MTU discovery
> > > implementations, because PMTUD depends on receiving ICMP
> > > unreachable/"fragmentation needed but DF set" errors from the
> > > bottleneck router.
> > I thought we would back off to a smaller packet size if we "lost
> > contact" after N seconds. Am I wrong?
> No. We try bigger packets after N seconds, and use the next-hop MTU
> suggested by the ICMP packet too big messages.
well, at least that's what the RFC says. I didn't look at our code recently.
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