# Can't get bridging started

## mlindholm

I'm trying to setup a bridge on a server I recently setup.  So far, everything is going suprisingly well on this box except getting the bridge going.  I've tried to search on here, and google for answers, but can't solve this problem.  When I compile the bridge into the kernel, running brctl will complain that bridging isn't installed.  When I compile as a module, I get the following errors:

```
modprobe bridge

/lib/modules/2.4.20-gentoo-r6/kernel/net/bridge/bridge.o: unresolved symbol br_ioctl_hook

/lib/modules/2.4.20-gentoo-r6/kernel/net/bridge/bridge.o: unresolved symbol nf_hooks

/lib/modules/2.4.20-gentoo-r6/kernel/net/bridge/bridge.o: unresolved symbol br_handle_frame_hook

/lib/modules/2.4.20-gentoo-r6/kernel/net/bridge/bridge.o: unresolved symbol nf_hook_slow

/lib/modules/2.4.20-gentoo-r6/kernel/net/bridge/bridge.o: insmod /lib/modules/2.4.20-gentoo-r6/kernel/net/bridge/bridge.o failed

/lib/modules/2.4.20-gentoo-r6/kernel/net/bridge/bridge.o: insmod bridge failed

```

I'm not sure what I need to do that I haven't already done.  I read to do the following and check for output similar to what follows:

```
grep br_ /proc/ksyms

c0343f94 br_fdb_get_hook_R650128e7                                                                                        

c0343f98 br_fdb_put_hook_Rb494e82a                                                                                        

c03411e0 br_handle_frame_hook_R60411b88                                                                                   

c03d0c80 br_ioctl_hook_R1fb9705f

```

When I did that, I got some, but not all:

```
c013d7b4 br_handle_frame_hook_R__ver_br_handle_frame_hook

c017f440 br_ioctl_hook_R__ver_br_ioctl_hook

```

Anybody out there have any ideas?  I just installed this server within the last week, using a stage 3 tarball, and it just finished "emerge -u world"ing, (though hasnt been rebooted since), so everything should be rather fresh.

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## BradN

try doing a "make mrproper" on your linux source tree - this will delete your .config though, so back it up first.  Sometimes this solves weird dependency issues.

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## mlindholm

I've been using "genkernel --config" to compile my kernel, doesn't that run "make mrproper" ?  I've considered doing that, but I wasn't sure if it would have any negative effect or not.

edit:  I use "genkernel --config" so I can select options (example: remove all unnecessary modules/kernel supports, such as SCSI support, ISDN, IrDA, etc; I also add in things I want, like wireless (non-ham) support, bridging, and such.Last edited by mlindholm on Fri Sep 19, 2003 6:21 pm; edited 1 time in total

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## acidreign

I dont know if genkernel actually builds a kernel that can do bridging, but there is a good document on making this happen on the Gentoo Server Project page.

http://www.subverted.net/wakka/ search for bridge.

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## mlindholm

I just ran "make mrproper", then reran "genkernel --config", and it's currently rebuilding the kernel/modules.  I'll try it again when I get home from work. . .if that fails, I'll try to build it the old fashioned way.  :Smile: 

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## BradN

I built a kernel with bridging support on my laptop before, but it didn't work for what I wanted due to the wireless card locking to a specific mac address.  As you mentioned, try building a kernel by hand if genkernel doesn't work right.

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## mlindholm

 *Quote:*   

> ....locking to a specific mac address

 

what do you mean by this?

After running "emerge -u world", I had a BUNCH of problems modprobing "bridge.o" (when i ran "modprobe bridge" that is).  Ran "make mrproper", recompiled the kernel with the same options, using "genkernel --config" (with the updated GCC, etc), and tried again after a reboot.  Success!

I was able to load "bridge.o", run "brctl add br0", and go through the process of configuring a bridge. . .now I just need to get it to pass traffic!

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## BradN

My project was to allow computer(s) to connect to the ethernet on my laptop and get network access via my laptop's wireless card.  Well, the prism2 (prism2.5?) pcmcia card I use has firmware that only allows transmitting as one mac address.  To bridge effectively, you need to be able to transmit with any mac address to send messages from other computers - therefore the problem.

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## mlindholm

I think that's what's giving me problems now, I've got it setup, but it won't transfer data (a wired client can't get an address from the WAP's DHCP server over wireless).  Also, I can't ping over it. . .depending on how it's setup, I can ping the bridge's IP, but not necessarily through both interfaces.  Oh well. . .after getting to this point, I could possibly get further and make it work, but I think I'll just use IP Masquerading.

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