Re: The IPv4 Internet MTU

[Rémi Denis-Courmont <rdenis@simphalempin.com>]

	Hello,

Le Thursday 11 October 2007 22:20:35 Brian E Carpenter, vous avez écrit :
> On 2007-10-12 05:52, Templin, Fred L wrote:
> > Brian,
> >
> >> So, is there any scope for a generic UDP echo process that would allow
> >> PMTUD without ICMP messages? It's probably easier to get a port open
> >> in firewalls for that than to reverse the trend of ICMP filtering, as
> >> long as the echo process has adequate DoS resistance.
> >
> > I would hope that we could at least ping. Or, is that
> > off the table as well?
>
> If you mean ICMP echo that seems to be blocked in many places.

By design, ICMP echo requests can't go *in* through NATs anyway, so this is a 
moot point within this *TEREDO* thread..

Of course, UDP echo would work, but I am a bit concerned as to its 
applicability to potentially short-lived UDP flows, as can happen with 
TEREDO... ?

-- 
Rémi Denis-Courmont
http://www.remlab.net/