In article <200601261959.OAA00374@Sparkle.Rodents.Montreal.QC.CA>,
der Mouse  <mouse@Rodents.Montreal.QC.CA> wrote:
>>> The real problem is on the other end: hosts which try to do PMTU-D,
>>> but are behind boxes (usually misconfigured firewalls) which drop
>>> the ICMPs necessary for PMTU-D to function.
>> Not only, some PPPoE setup just won't send the ICMP unreachable
>> message, because the equipement at which the MTU is lowered doesn't
>> appear at the IP level.
>
>You mean things like ATM?  But that won't listen to the DF bit, either,
>will it?  So there's no issue (except the loss rate increase provoked
>by fragmentation).

>Or you mean there are setups which silently drop too-large packets
>without any notification to anyone?  I have trouble calling those
>anything better than grossly broken, and wouldn't worry about arranging
>for NetBSD to support them any more than I would about doing likewise
>for setups which, for example, drop packets containing 0xff octets:
>it's the responsibility of the IP-over-whatever layer to actually
>implement IP's semantics.

Welcome to my Verizon setup :-) But for 15Mbits downstream @
$49.95/month I'll turn on MSS clamping... I was an early
adopter so I actually get 30Mbits @ $49.95.

christos