Help with wireless bridge

Wed Apr 21 13:14:45 UTC 2004

Andrew Cocker wrote:
> Hi
> Can anyone either help or tell me a better place task for it. I need help
> setting up a wireless
> <http://www.experts-exchange.com/Networking/Linux_Networking/Q_20957382.html
> 
>> bridge on my Fedora Core 1 server
> 
> <http://www.experts-exchange.com/Networking/Linux_Networking/Q_20957382.html
> 
>>. This Windows XP
> 
> <http://www.experts-exchange.com/Networking/Linux_Networking/Q_20957382.html
> 
>> PCs. I want to extend this network wirelessly to my Dell Centrino
> 
> portable. 
> 
> I reconfigured the kernel with wireless and bridge support and installed a
> generic 8180 wireless card using ndiswrapper. I have configured it so: 
> iwconfig wlan0 channel 1
> iwconfig wlan0 mode Ad-Hoc
> iwconfig wlan0 essid any
> ifconfig wlan0 192.168.1.10 broadcast 192.168.1.255 netmask 255.255.255.0. I
> have copied the output from ifconfig and iwconfig below. The portable now
> detects its presence so the card must be working OK.
> 
> I think I want a simple bridge which just sends/receives packets from eth0
> to wlan0, no fancy tricks. But if I create a bridge like this:
> Brctl addbr br0
> Brctl addif br0 etho
> Brctl addif br0 wla0
> 
> then it doesn't work and the network stops. What do I need to do?  (I know I
> need to add encryption and change the ESSi later for securit reasons
> 
> Thanks in advance Andrew
> 
> IFCONFIG 
> 
> eth0 Link encap:Ethernet HWaddr 00:04:E2:0E:02:8A 
> inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:3388 errors:0 dropped:0 overruns:0 frame:0
> TX packets:3009 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000 
> RX bytes:480517 (469.2 Kb) TX bytes:956396 (933.9 Kb)
> Interrupt:12 Base address:0xd000 
> 
> eth1 Link encap:Ethernet HWaddr 00:40:F4:5F:04:1A 
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:547 errors:0 dropped:0 overruns:0 frame:0
> TX packets:577 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000 
> RX bytes:226238 (220.9 Kb) TX bytes:67785 (66.1 Kb)
> Interrupt:3 Base address:0x5000 
> 
> lo Link encap:Local Loopback 
> inet addr:127.0.0.1 Mask:255.0.0.0
> UP LOOPBACK RUNNING MTU:16436 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:0 
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
> 
> ppp0 Link encap:Point-to-Point Protocol 
> inet addr:61.9.182.4P-t-P:61.9.128.251 Mask:255.255.255.255
> UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1492 Metric:1
> RX packets:483 errors:0 dropped:0 overruns:0 frame:0
> TX packets:514 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:3 
> RX bytes:211688 (206.7 Kb) TX bytes:54418 (53.1 Kb)
> 
> wlan0 Link encap:Ethernet HWaddr 00:40:F4:5E:62:D2 
> inet addr:192.168.1.10 Bcast:192.168.1.255 Mask:255.255.255.0
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000 
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
> Interrupt:5 Memory:ea000000-ea0000ff 
> 
> IWCONFIG
> 
> wlan0 IEEE 802.11b ESSID:"any" Nickname:"wire"
> Mode:Ad-Hoc Frequency:2.412GHz Cell: 02:E0:8E:7D:9C:80 
> Bit Rate=11Mb/s Tx-Power:20 dBm Sensitivity=0/3 
> RTS thr=2432 B Fragment thr=2432 B 
> Encryption key:off
> Power Management:off
> Link Quality:100/100 Signal level:-95 dBm Noise level:-256 dBm
> Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
> Tx excessive retries:0 Invalid misc:0 Missed beacon:0
> 
> 
> 
> 

I have a bridge setup between two Ethernet cards. I've not tried it between 
an Ethernet and wireless card but the principle should be the same. I don't 
know if the bridge will work if the interfaces have IP numbers assigned, I 
set them to 0.0.0.0 (after all, once the bridge is running the interfaces 
themselves should be transparent to the network). They need to be in 
promiscuous mode.

This is the startup procedure I follow:

     brctl addbr bridge
     brctl addif bridge eth0
     brctl addif bridge eth1
     ifconfig eth0 promisc 0.0.0.0
     ifconfig eth1 promisc 0.0.0.0

The network scripts for these two interfaces 
(/etc/sysconfig/network-scripts/ifcfg-eth0, ifcfg-eth1) both specify ONBOOT=no.

If you need to contact the machine then configure the bridge interface by 
creating ifcfg-bridge in /etc/sysconfig/network-scripts. This is mine:

DEVICE=bridge
BOOTPROTO=static
BROADCAST=xxx.xxx.xxx.255
IPADDR=xxx.xxx.xxx.xxx
NETMASK=255.255.255.0
NETWORK=xxx.xxx.xxx.0
ONBOOT=yes
TYPE=Ethernet
USERCTL=no
PEERDNS=no

the bridge interface will then listen at the specifed IP address.

-- 
Nigel Wade, System Administrator, Space Plasma Physics Group,
             University of Leicester, Leicester, LE1 7RH, UK
E-mail :    nmw at ion.le.ac.uk
Phone :     +44 (0)116 2523548, Fax : +44 (0)116 2523555