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. > > -- > > > 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