26 Sep
2013
26 Sep
'13
4:13 a.m.
However for some reason path MTU discovery has completely broken when using the newer modem. The primary Linux box is fine, but all clients (whether wired, wireless *or even virtual*) fail to work unless I manually set their interfaces to an mtu of 1492.
Is it outbound or inbound MTU path discovery that isn't working? Or both? I've had to set MRU explicitly before to get things working properly, although I don't see why the different modem would make a different, unless it was using baby jumbo frames or something. What does 'ip link show dev ppp0' say? Is MTU definitely 1492 in there? What happens when a client computer tries to send a larger packet? Does your Linux router send a 'frag required' response? James