I have two WRT boxen; Alice and Bob.

I want Alice to listen in promiscius mode on, let's say, the WAN port. All packets that come to that interface should be put into some kind of wrapping, and sent to Bob over the LAN. Bob takes the packets he gets from Alice, takes them out of their wrapping, and sends them out again on his WAN port. The reverse should also be possible, i.e. Bob listening and sending all packets to Alice. This tunnel would be on Layer 2 in the OSI model, because Alice and Bob will be hearing TCP, UDP, DHCP, IGMP etc. and this is what I want to forward.

Is there an implementation of this, is it possible at all?

vtun?  http://vtun.sourceforge.net/
can bridge two or more ethernets on L2 (broadcasts, everything, even not IP protocols), over any IP capable network. Low resource usage, works with wrt54gl, very small and reliable.

(Last edited by netmaster on 26 Jul 2007, 16:12)

Looks cool,I will try it when i come home from Scotland...

if your sending these packets over an ethernet lan, it's seems a perfect use for vlans (ethernet over ethernet tunnel), rather then ethernet over ip.

There is etherip: RFC 3378. OpenBSD implements it. A patch was given for Linux here: http://lwn.net/Articles/199120/

Otherwise, OpenVPN has a bridging mode which may do what you want. http://openvpn.net/bridge.html

I could not get it working when i last tried, do you have any configuration files for it?

Does OpenWRT have support for vlans "outside" of the box?