[137087] in North American Network Operators' Group
Re: Too bigs are sacred, was: Re: IPv6 addressing for core network
daemon@ATHENA.MIT.EDU (David Freedman)
Wed Feb 9 12:51:39 2011
To: nanog@nanog.org
From: David Freedman <david.freedman@uk.clara.net>
Date: Wed, 09 Feb 2011 17:50:35 +0000
X-Complaints-To: usenet@dough.gmane.org
In-Reply-To: <29708DA0-57F6-4AFD-B11A-ED5AD399FFF6@muada.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Iljitsch van Beijnum wrote:
> On 9 feb 2011, at 18:30, David Freedman wrote:
>
>> (yes, even ICMP TOOBIG
>> can be filtered safely if you have designed things in a sane way)
>
> NO.
>
> Even if you run with 1280-byte MTUs everywhere so you'd think path MTU discovery wouldn't be needed, this can still cause problems with IPv6-to-IPv4 translators.
>
Calm down, I think you misunderstand,
I'm suggesting that you don't design your infrastructure in such a way
that your backbone/infrastructure links ever have to receive TOOBIG
messages from outside your AS and work with these, your backbone links
are of course free to send TOOBIG out!
Dave.
--
David Freedman
Group Network Engineering
Claranet Group
