On Monday, 08 January 2007 at 09:08, Ben Greear wrote: > Hello! > > I am curious if a single machine can be made to look like several > routers. Please consider the following > configuration: > > Linux Router-A has 4 ethernet interfaces. PC-A is connected to eth0 and > has IP 192.168.0.2. > eth0 on Router-A has IP 192.168.0.1/24 > eth1 has IP 192.168.1.1/24, and eth1 is connected directly to eth2 > eth2 has IP 192.168.2.1/24 > eth3 is connected 'upstream' and has IP 192.168.3.1/24 > > I would like for PC-A to be able to ping 192.168.0.1 and 192.168.1.1 as > normal. > The part I'm not sure how to make work is that I want to be able to ping > 192.168.2.1 and > have the packet route out of eth1 and into eth2 (PC-A -> eth0 -> eth1 -> > eth2), and have the return packet follow the > eth2 -> eth1 -> eth0 -> PC-A path. A trace-route from PC-A should show > each of these hops (or, at least eth0 and eth2.) > > The eventual goal is to have arbitrary numbers of 'routers' in a single > Linux machine for emulation > purposes. > > I was thinking that I might could accomplish this using multiple routing > tables and perhaps > specific subnet routes for each each virtual router, specifying which > interface the packets should > leave in order to find the next hop. > > Has anyone tried something similar to this or have ideas for how to best > proceed?
I started something like this a while ago (posted at <[EMAIL PROTECTED]> with a couple of replies by Thomas Graf, but I can't seem to find it in the archives) but then dropped the ball. It seems to work fairly well with a one-line kernel patch to allow route lookup before the local address check. Oh, and I didn't get traceroute working quite right either - I think there was some trick to finding the source address for the generated reply. I've got some info and code here: http://dsg.cs.ubc.ca/~brendan/remus/ - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
