I am confused regarding MTU issues and bridging.
I have setup an bridge with an MTU of 1492 for the bridge and all the
devices in the bridge.
I setup the device interface on one leg of the bridge to have an MTU of
1492 as well. I mount an nfs share on another leg of the bridge. This
device has an MTU of 1500 and I get problems with the nfs mount until I
set the MTU to 1492. Do I have to set all devices on the bridge to have
an MTU of 1492 for the bridge to work? The reason I am confused is that
the if the two devices are connected directly with one having an MTU of
1492 and the other 1500, things work. However, putting the bridge
between them requires setting both devices to have an MTU of 1492.
Here is the bridge setup:
root at bug20:~# brctl show br0
bridge name bridge id STP enabled interfaces
br0 8000.0050c269c63f no eth0
usb0
root at bug20:~# ifconfig -a
br0 Link encap:Ethernet HWaddr 00:50:C2:69:C6:3F
inet addr:192.168.75.133 Bcast:192.168.75.255
Mask:255.255.255.0
inet6 addr: fe80::250:c2ff:fe69:c63f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1492 Metric:1
RX packets:128521 errors:0 dropped:0 overruns:0 frame:0
TX packets:45471 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:163191890 (155.6 MiB) TX bytes:39435311 (37.6 MiB)
eth0 Link encap:Ethernet HWaddr 00:50:C2:69:C6:3F
UP BROADCAST RUNNING MULTICAST MTU:1492 Metric:1
RX packets:44140 errors:0 dropped:0 overruns:0 frame:0
TX packets:60299 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:16728060 (15.9 MiB) TX bytes:79965979 (76.2 MiB)
usb0 Link encap:Ethernet HWaddr D2:D0:1C:9A:35:8F
inet6 addr: fe80::d0d0:1cff:fe9a:358f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1492 Metric:1
RX packets:13914 errors:0 dropped:0 overruns:0 frame:0
TX packets:7373 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:20359268 (19.4 MiB) TX bytes:778806 (760.5 KiB)
Thanks,
Lane