Share your knowledge at the LQ Wiki.
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 10-30-2005, 11:53 AM   #1
LQ Newbie
Registered: Jan 2004
Distribution: Fedora Core
Posts: 24

Rep: Reputation: 15
Question Bridge connectivity problems

I am attempting to upgrade my linux router by adding an AP function (since my old netgear AP kicked the bucket). It strikes me that I should have better/more powerful tools and controls on a linux AP, plus less running hardware = happier wife.

Currently the machine has four NIC cards:

eth0 - attached to the internet via Cable Modem
eth1 - wired attachment to my local LAN
ath0 - Madwifi 802.11a Turbo capable WIFI Adapter
wlan0 - Prism based 802.11b WIFI Adapter

At various points, I have had both ath0 and wlan0 functioning successfully as WIFI access points. Currently, I have eth1, ath0, and wlan0 combined into a bridge called br0. That way they all share DHCP. I am able to connect 802.11b and see the internet. I am also able to connect wired and see the internet. However, I cannot see a device on my internal wired LAN from my wireless or vice versa. My understanding is that this is exactly what a bridge should enable me to do. Hence I am confused. Here is my bridge setup (from rc.local):

# Set up bridge to handle access point services
ifconfig eth1
ifconfig wlan0
ifconfig ath0
brctl     addbr br0
brctl     addif   br0 eth1
brctl     addif   br0 wlan0
brctl     addif   br0 ath0
ifconfig br0 netmask up
brctl stp br0 off
There are some other issues in my config I'd like to get fixed, but for the immediate... How do I get my wireless LAN talking to my wired LAN? Here is the route table as well:

# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface     *        U     0      0        0 br0   *        U     0      0        0 eth0     *          U     0      0        0 eth0
default         UG    0      0        0 eth0
My only success getting the interfaces to talk to one another has been through making br0 the default gateway, and thus losing internet connectivity.

For the sake of completeness, I am running a firewall. It is the rc.firewall-2.4-stronger ver 0.80s available here:

I apologize. My issues seems like it's probably a simple mis-config on my part. But it has been troubling me for a long time, and I have been unable to google a solution. Any suggestions you may have are greatly appreciated.


Last edited by tedcox; 10-30-2005 at 11:55 AM.
Old 10-31-2005, 03:38 PM   #2
LQ Newbie
Registered: Jan 2004
Distribution: Fedora Core
Posts: 24

Original Poster
Rep: Reputation: 15
bump. Anyone have any ideas?
Old 10-31-2005, 05:20 PM   #3
Registered: Jan 2005
Location: Cork Ireland
Distribution: Debian
Posts: 384

Rep: Reputation: 32

i didn't check your firewall, so excuse me if you already configured this...
you must enable forwarding from br0 to br0, because packets using the bridge go through iptables as well: iptables -A FORWARD -i br0 -o br0 -j ACCEPT
Old 10-31-2005, 06:50 PM   #4
LQ Newbie
Registered: Jan 2004
Distribution: Fedora Core
Posts: 24

Original Poster
Rep: Reputation: 15
THAT DID IT! Thank you so much! As I suspected, that should have been obvious to me, but for whatever reason it wasn't. Happy Halloween.


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
Eth0 connectivity problems gastondip Linux - Newbie 5 05-01-2006 05:59 AM
Wireless connectivity problems Jerel Linux - Newbie 1 09-04-2005 09:17 AM
Printer connectivity problems jws8 Linux - Hardware 4 08-03-2005 09:39 AM
Problems with connectivity Viper168 Mandriva 8 10-23-2003 01:47 PM
Connectivity problems Palin Linux - Networking 1 04-14-2003 08:13 PM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 06:20 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