Hello,
so given that fragmentation is disallowed the PMTU discovery always needs to work and the wireguard MTU needs to be correctly adjusted. Speaking of a DC situation, I think this might be tricky. Imagine the following situation: - endhost A has an MTU of 9k. PMTU 9k. wg 8920. - the path changes, the PMTU reduces to 1.5k (this is something we see happening from time to time) - How is the wg MTU adjusted in this situation? And to clarify: with disallowing IP frag, you are obviously only referring to the outter transport. Within the tunnels, IPv6 and IPv6 packets can still be fragmented, so application operation is not really affected. Interesting approach, I am not really sure if realisticly feasible, especially when thinking about long range/low bandwidth media where you'd basically say "wg cannot do IPv6 on these mediums". Satelite systems should probably work fine, I am more concerned about mesh networks, in which wg is quite popular already. Cheers, Nico -- Sustainable and modern Infrastructures by ungleich.ch