Re: [Bridge] Ubuntu: network bridging between wireless and wired connection fails

["Nicolas de Pesloüan" <nicolas.2p.debian@free.fr>]

Jochen Hebbrecht wrote:
> Nicolas de Pesloüan schreef:
>>
>> Can you also explain why you are trying to use bridge ?

> Nicolas,
> 
> I'm not sure that bonding is the thing I need. I'll explain what I want 
> to do.
> 
> Please check this image: http://www.jochus.be/brol/networking.png
> * Purple lines: wired (UTP)
> * Blue (dashed) lines: wireless
> 
> So in this building, there are 2 locations. Location A and B. There's no 
> possibility to link them using a wired cable, and I don't like the net 
> adapters who transmits packets using the 50Hz channel.
> 
> In location A, there's a desktop and a notebook a. In location B, 
> there's a notebook, a server which maintains e-mails, backup, 
> Subversion, Archiva, ... and there's also printer (a network printer).

Ok, now we understand what you are trying to do. In particular, I assume 
the DHCP server is on the subnet of location B (or behind a router 
connected on this subnet), so the expected DHCP offer will come from the 
wire interface (eth0) and definitely not from the wireless interface 
(eth1).

> So, notebook B needs to print to the network printer, which is very easy 
> by using the switch that's on location B. So that works. But now I want 
> to print from location A on the desktop and notebook A. So I needed to 
> connect them in the same subnet of the networkprinter.

Let's try a step-by-step bridge configuration :

1/ Try to setup a non-bridge configuration and ensure you successfully 
get a DHCP answer using eth0.

auto eth0
iface eth0 inet dhcp

#auto eth1
#iface eth1 inet dhcp
#wpa-driver wext
#wpa-ssid ##SSID##
#wpa-ap-scan 1
#wpa-proto RSN
#wpa-pairwise CCMP
#wpa-group CCMP
#wpa-key-mgmt WPA-PSK
#wpa-psk ##PSK KEY##

#auto br0
#iface br0 inet dhcp
#bridge_ports eth0 eth1

2/ Try to setup a bridge with only eth0 (wire interface) and ensure this 
work well, using a static IP address.

#auto eth0
iface eth0 inet manual

#auto eth1
iface eth1 inet manual

auto br0
iface br0 inet static
bridge_ports eth0
address 192.168.1.111
netmask 255.255.255.0

3/ Try to setup a bridge with only eth0 (wire interface) and ensure this 
work well, using DHCP.

#auto eth0
iface eth0 inet manual

#auto eth1
iface eth1 inet manual

auto br0
iface br0 inet dhcp
bridge_ports eth0

4/ Then add the eth1 (wireless interface).

#auto eth0
iface eth0 inet manual

auto eth1
iface eth1 inet manual
wpa-driver wext
wpa-ssid ##SSID##
wpa-ap-scan 1
wpa-proto RSN
wpa-pairwise CCMP
wpa-group CCMP
wpa-key-mgmt WPA-PSK
wpa-psk ##PSK KEY##
# The wpa-bridge option is expected to instruct wpa_supplicant
# to listen on br0 instead of eth1. This is a workaround which
# should net be necessary after kernel 2.6.28 or 2.6.29, for
# as far as I remember.
wpa-bridge br0

auto br0
iface br0 inet dhcp
bridge_ports eth0 eth1

5/ If the previous fail, can you please test the following configuration:

#auto eth0
iface eth0 inet manual

#auto eth1
iface eth1 inet manual

auto br0
iface br0 inet dhcp
bridge_ports eth0 eth1
# the wpa-iface option is expected to instruct wpa_supplicant
# to setup the wifi link using eth1 instead of br0.
wpa-iface eth1
wpa-driver wext
wpa-ssid ##SSID##
wpa-ap-scan 1
wpa-proto RSN
wpa-pairwise CCMP
wpa-group CCMP
wpa-key-mgmt WPA-PSK
wpa-psk ##PSK KEY##
# The wpa-bridge option is expected to instruct wpa_supplicant
# to listen on br0 instead of eth1. This is a workaround which
# should net be necessary after kernel 2.6.28 or 2.6.29, for
# as far as I remember.
wpa-bridge br0

6/ If all this fail, please try the above (#5), without the wpa-bridge 
option.

7/ If all this fail... let's try something really different (and totally 
out of topic for the bridge list, sorry guys) :

Why do you need location A to be in the same subnet as the printer in 
location B ? The Ubuntu server in location B might be setup as a normal 
router (with two different IP in two different subnets). Then, the 
default route on the printer should be set to the LAN IP address of the 
ubuntu server.

If you cannot change de default route for the printer, then add a route 
on the router of this subnet. This new route should ask the router to 
forward packet for the subnet of  location A through the Ubuntu server.

If you cannot change de routing table in this router, then I suggest you 
try some sort of NAT configuration to arrange for all host in location A 
to be NATted to an IP address of location B subnet (using proxy ARP).

	Nicolas.

> So, I wanted to created a bridge on the Ubuntu server (who has a 
> wireless WMP54G network card), and on eth0 an ethernet controller. So by 
> connecting eth0 to the switch, all notebooks and desktop would be able 
> to print to the networkprinter
> 
> This situation works fine if the server is running Windows, but not 
> Ubuntu as the bridge isn't working there :-(