On Feb 9, 2011, at 9:50 AM, David Freedman wrote:
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.
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David Freedman Group Network Engineering Claranet Group
Unless every packet you emit is ≤ the minimum MTU (1280), then, you need to be able to receive TOOBIG messages. Owen