<quote who="Sonia Hamilton">
> Is it possible to setup a linux box as a transparent bridge?
>
> The reason is that I'm routing an ip range, and I want to stick a Linux
> box in the middle, just for ip accounting purposses.
>
> I know I can use proxy-arp to do this; seems a bit messy.
Yeah, totally. I'm a big fan of the bridging stuff in Linux - including
firewalling! Seriously sweet.
I forget what the bridging module is called (it's built into my kernel), but
it ought to load once you start trying to set up the bridge. The manual way
to do it is with brctl, which is fairly obtuse, but it works. You can set up
a bridge without ip addresses at all, with a single ip address on the bridge
interface (br0), or with an ip address on each interface. Very useful.
If you happen to be running Debian, setting a bridge is outrageously simple,
compared to using brctl. You just add a stanza to your interfaces file like
this:
auto br0
iface br0 inet static
address 192.168.10.1
netmask 255.255.255.0
bridge_ports eth1 eth2
That sets up a bridge between eth1 and eth2, with an ip address. If you ifup
br0, the ifupdown scripts handle setting up the bridge for you. It's very
sweet.
Adding firewall stuff includes patches and stuff, but I'd be happy to do a
show and tell sometime if anyone's interested.
- Jeff
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linux.conf.au 2004: Adelaide, Australia http://lca2004.linux.org.au/
"What inspired you to become a bus driver?"
"Linus Torvalds."
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