On Friday 2012-04-20 19:30, Rick Jones wrote: > > I suspect the answer is some variation on: > > c) Since the two systems are in the same broadcast domain, with no intervening > router to perform PathMTU discovery, the PC will send IP datagrams up to 1500 > bytes, which likely as not will be dropped by the "router" as being too large > before it even gets to IP on the router. > > I would expect that only if your "router" has a 1500 byte MTU on the interface > facing the PC, and a 1492 byte MTU on the interface facing the "internet" would > you see the PathMTU discovery activity which would cause the PC to adjust the > effective MTU it was using to match 1492. Only if the IPv4 DF (Don't Fragment) > bit is clear should the "router" split the packets. Nope, if DF is set, no splitting is allowed and the appropriate ICMP message is generated. And exactly that is how PMTU is discovered. -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
