3 ms·
IP fragmentation is different in IPv6 true. MSS is a TCP parameter, however, and operates at layer 4. Won’t matter if the protocol underneath is IPv4 or IPv6
by topranks 7y ago
IP fragmentation is different in IPv6 true.
MSS is a TCP parameter, however, and operates at layer 4. Won’t matter if the protocol underneath is IPv4 or IPv6 in this case.
- peterwwillis 7y agoActually, it does behave differently. Never underestimate the weirdness of IPv6 ;-) From https://en.m.wikipedia.org/wiki/Maximum_segment_size https://en.m.wikipedia.org/wiki/Maximum_segment_size : "To avoid fragmentation in the IP layer, a host must specify the maximum segment size as equal to the largest IP datagram that the host can handle minus the IP and TCP header sizes.[2] Therefore, IPv4 hosts are required to be able to handle an MSS of 536 octets (= 576[3] - 20 - 20) and IPv6 hosts are required to be able to handle an MSS of 1220 octets (= 1280[4] - 40 - 20)." So it seems like one needs to clamp tcpv4 to at least 536, and tcpv6 to at least 1220. (tcpv6 is common shorthand for TCP over IPv6, similar to udpv6 and icmpv6)