On Tue, 11 Feb 2003, Damien Miller wrote: > Quite possibly the final word on the matter: > > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=58084
Daniel finally figured out why they use DF on fragments: "The missing piece in the puzzle was the fact that certain protocols like NFS can't split transactions/operations into smaller packets, they need to send the entire transaction in one single (complete) IP packet. This size might exceed any real MTU, so it will get fragmented first. And only afterwards PMTU discovery gets applied to the fragments. Hence, DF on fragments. This scheme is not explicitely covered by the RFCs, but I agree that it's a logical conclusion." http://kerneltrap.org/node.php?id=579&cid=2386&pid=2382#2386 Cheers, Dries
