Linux ethernet bridge : route configuration

medized · 05-18-2010, 01:01 PM

Hello all

!

I have two Network Interfaces eth0 and eth1. For each one of them, I have two ip aliases:

Code:

eth0:0 192.168.0.1 
eth0:1 192.168.0.2

eth1:0 192.168.1.1 
eth1:0 192.168.1.2

I put a bridge between the two interfaces:

Code:

brctl addbr br0
brctl addif br0 eth0
brctl addif br0 eth1

I built a program which sends packets from 192.168.0.1 to 192.168.1.1 and from 192.168.0.2 to 192.168.1.2, using raw sockets to be able to forge the ip source and destination fields.

The packets are delivered, but through the loopback interface. I actually need it to go from eth0 to eth1 ... I guess I have to configure some special routes, but I don't which ones.

I'd like to be able to specify to the kernel to use the eth0 interface when the address is 192.168.0.* , and the eth1 interface for 192.168.1.* addresses, and let the bridge do the rest.

Thanks for your help, this question might sound stupid, but my networking skills are really, I mean really limited !

Cheers,

--
Zed

acid_kewpie · 05-19-2010, 06:13 AM

Well you're basically just not using a bridge at all correctly. by definition, a bridge is a device (or simulation of, in this case) that joins two similar ethernet segments as one, at Layer 2 in the OSI model. Basically this means that everything needs to be in the same ip subnet, just like a physical network switch. What are you trying to achieve by doing this? The point should be that machines hanging off of eth1 can talk directly to machines on eth0 without doing any routing, just switching, but that's only logically feasible if they are both in the same subnet, e.g. 192.168.0.0/24, and not one there and one in 192.168.1.0/24 instead.

pixellany · 05-19-2010, 06:58 AM

Moved to Linux-Networking