> -----Original Message----- > From: bridge-bounces@xxxxxxxxxxxxxx > [mailto:bridge-bounces@xxxxxxxxxxxxxx] On Behalf Of Henrik Nordstrom > > Eh.. I do not claim to be a bridge guru, but won't such bridge cause > serious havoc on the network much like PMTU blackholes does? > > You should either reject creating such bridge, IMO, the driver should not bridge any packets from a device with a larger MTU to a device with a smaller MTU, which I suppose is almost the same as forbidding such a bridge to be created, but I seem to remember Stephen's commenting that the 802 bridge spec says it should be done the way it is now. > or make sure to fragment packets including ICMP MUST > FRAGMENT generation when not allowed (which requires an IP). The ethernet bridge driver is the wrong place to do IP or any other higher-layer protocol. Its job is to be a LAN in a box. If a device claims that it can only send packets up to a certain size, the bridge honors that claim. If connection tracking is coalescing ethernet packets into a size greater than would otherwise be received from a device, then connection tracking should be responsible for undoing that damage (where and when, I don't know), otherwise the ethernet bridge driver will become a monstrosity of stuff unrelated to ethernet.
