bridge wont forward when ip address changes
hello :)
I have been using the bridge utils for a long time now and its been very good but there are a couple of issues that I came across when trying to setup a wireless bridge...
Firstly I currently have a setup like the following ...
Computer A --- Wired Network --- linux box ---- wireless link ------ linux box ----- Wired Network --- Computer B
I have bridged the wireless interfaces and the wired interfaces together on both of the linux box's and data can travel across the wireless bridge without any trouble but if I attempt to change the IP addresses / subnet of Computers A and B the bridges seem to stop forwarding packets and no data get through at all, its like they aren't learning the new addresses.
If I restart the 2 Linux boxes then everything starts flowing properly again.
The 'Linux boxes' are a couple of Motorola Wireless Access points running OpenWRT.
Does anybody know why this might be happening and what I might be able to do about it?
The other issue is that the this bridge setup doesn't seem to forward any NetBIOS traffic, however, i'm not too worried about this its more of just bring curious.
Thanks for your help,
Matty.
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Quoted 25 lines · Andy Gospodarek
Quoted 24 lines · Matt Richards
hello :)
I have been using the bridge utils for a long time now and its been very good but there are a couple of issues that I came across when trying to setup a wireless bridge...
Firstly I currently have a setup like the following ...
Computer A --- Wired Network --- linux box ---- wireless link ------ linux box ----- Wired Network --- Computer B
I have bridged the wireless interfaces and the wired interfaces together on both of the linux box's and data can travel across the wireless bridge without any trouble but if I attempt to change the IP addresses / subnet of Computers A and B the bridges seem to stop forwarding packets and no data get through at all, its like they aren't learning the new addresses.
If I restart the 2 Linux boxes then everything starts flowing properly again.
The 'Linux boxes' are a couple of Motorola Wireless Access points running OpenWRT.
Quoted 9 lines
Quoted 3 lines
Does anybody know why this might be happening and what I might be able to do about it?
I wonder if this is ARP related? I've noticed some interesting behavior when bridging wired and wireless devices. Have you noticed that you can communicate after the IP switch if you send a gratuitous ARP from any of the wireless devices?
hello,
no i haven't tried tried that, i did notice that if i try to make a computer talk to another device after the ip change the arp table would contain the IP with an invalid state and no mac address or a mac address of all F's i think it was.
Sending arp packets wouldn't be a solution as this will be used in a computer lab to connect sockets that are in parts of the room where its not easy to run cables and therefore wouldn't be ideal for people to use when learning about network operating systems.
One thing I have just thought of, while reading an email from the openvpn mailing list, is that if i setup an openvpn tunnel with tap interfaces over the wireless link and bridge the switches to the tap interface then the problem should go away if it is to do with the wireless interfaces.
Is a little weird tho, I had to lower to mtu to get the devices to ping in the first place.
Matty.