[Gllug] Bridge problems (Ubuntu)

Adrian McMenamin adrian at mcmen.demon.co.uk
Tue Jun 28 08:52:37 UTC 2011

I thought I had all my bridge problems solved (bridging an ethernet and
wireless connection) but we had a powercut on Sunday night and as I had
set the bridge up on the command line rather than through
/etc/network/interfaces, I had to do that again and I just cannot get it
to come back up properly - the issue seems to be a routing one.

I have wasted a day of my life trying to fix this to no avail so hope that
someone here can identify what I am getting wrong - apologies for the
length and thanks for your forbearance.

This is a small home network with the commodity router (a really poor
piece of kit but which supports Talk Talk's video streaming so needs to
stay) and the box on which I am trying to bridge the interfaces on all the
time. The box provides squid proxy, DNS, email and a web server (webmail -
as I am using now) to the network, so really needs to be reachable!

The box's ethernet address is - which has to be preserved
(or at least it has to come back at a known address every time given the
services it provides to the network).

So - typically... (with wlan0 under hostapd control)

I have

auto eth0 wlan0
iface eth0 dhcp

Then go to command line and type:

sudo brctl addbr br0
sudo brctl stp br0 on  # have some other bridges (eg plug adapters) on
sudo brctl addif br0 eth0 wlan0
sudo ifconfig br0 up

Typically this results in a complete loss of routing ie I cannot even ping (commodity router) from this box

Any clues?

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