Review your favorite Linux distribution.
Go Back > Forums > Linux Forums > Linux - Networking > Linux - Wireless Networking
User Name
Linux - Wireless Networking This forum is for the discussion of wireless networking in Linux.


  Search this Thread
Old 04-01-2006, 02:58 PM   #1
LQ Newbie
Registered: Apr 2006
Posts: 4

Rep: Reputation: 0
Bridging Wireless interface with the Wired one

Dear forum members,
I have been googling around for almost 7 days now trying various samples and suggestions and still cannot figure out how to solve the following issue:
I have a linux box (Fedora core 5, 2.6.15) with two NICs installed: One 10/100 Ethernet and one Wireless 802.11b (Cisco Aironet 350 PCI). My purpose is to bridge those two interfaces (eth0 - wireless, eth1 - wired), so that the computers on both sides exchanged traffic as if they were on the same physical network, on the same subnet.
First I tried to bridge those two connections with "brctl" utility to act as a layer 2 bridge: created a new bridge (brctl addbr br0), then added those two interfaces to the bridge (brctl addif br0 addif eth0, eth1). For ease of administration, I also added an IP address to the bridge interface br0 itself (, meanwhile removing all IP information from eth0 and eth1 interfaces (as per to most tutorials available on google).
Having all this configured, I am now able to ping to both sides of the network: wireless over eth0 and wired, over eth1. Meanwhile both sides can reach the Linux box as well. But the problem is that the hosts themselves cannot reach each other.
After spending another day in google, I figured out that some wireless cards might not work in layer 2 bridging mode. I supposed that mine was the case.
Next I figured out the key to solution could be using "Proxy ARP" technology. I tried to use the "parprouted" deamon. It worked, but partially! Now ICMP packets (pinging) were successfully passing between clients in both interfaces, but nothing more. I could not even open a port on remote host with telnet. The deamon's manual implies that it is possible to pass unicast traffic between hosts, but at least it did not work in my case.

Now my request is to all people who can assist me in setting up this network scenario. Is it possible to do it through Proxy ARP? What routes should be added? What should be altered in iptables' chains? Any hint is highly appreciated.

Client 1...............((((((((.. )))))))............ Linux Box with bridge ___________________ Client 2, eth1, br0...............Ethernet..............

Thank You.
Best Regards,
Old 04-02-2006, 08:47 PM   #2
LQ Newbie
Registered: Apr 2006
Posts: 4

Original Poster
Rep: Reputation: 0
Just an update:

I tried to enable "Proxy ARP", on my linux box.
echo > 1 /proc/sys/net/ipv4/conf/eth0/proxy_arp
echo > 1 /proc/sys/net/ipv4/conf/eth1/proxy_arp

Now I can ping to the internet, from a client (
Now the problem is that nothing else is working except PING. No DNS, no http... nothing.

Any ideas?
Old 04-03-2006, 08:50 AM   #3
Registered: Apr 2003
Location: boston
Distribution: ubuntu debian redhat fedora
Posts: 108

Rep: Reputation: 15
i'm not sure if this is needed for this setup, or why a ping gets through, but try enabling ip_forwarding

echo 1 > /proc/sys/net/ipv4/ip_forward
Old 04-04-2006, 04:49 PM   #4
LQ Newbie
Registered: Apr 2006
Posts: 4

Original Poster
Rep: Reputation: 0
Thank you Bardinjw for the advice, but I have enabled IP forwarding before.
The problem is solved other way.
First I added a route to eth0 wireless interface.
route add -net netmask dev eth0
I am not sure why, but I also flushed the iptables, and it worked !!
iptables --flush
I guess there was something that blocked non-ICMP packets pass through.
Anyway, thanks everybody for attention.



Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Bridging a wired network to a wifi network bobmcobob Linux - Wireless Networking 2 07-18-2008 07:36 PM
Wired interface priority over wireless in Debian Debian_Poland Linux - Wireless Networking 5 02-03-2006 12:51 PM
Wireless Laptop to Wired ethernet via Linux PC (wired/wireless) sambartle Linux - Wireless Networking 0 01-30-2005 05:37 AM
Laptop-net on wired/wireless interface blueplazma Linux - Wireless Networking 2 12-24-2004 03:29 PM
Wired to Wireless back to Wired The_Nerd Linux - Hardware 5 09-15-2004 10:20 PM > Forums > Linux Forums > Linux - Networking > Linux - Wireless Networking

All times are GMT -5. The time now is 08:51 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration