So, the zeroconf/bonjour stuff that Apple uses only works on the same local network, you can't see people in other segments. This is because they use 224.x.x.x address which will not pass through a router. I'm thinking that with some fancy iptables work and a linux box, I could tell it to "NAT" those packets to a 239.x.x.x multicast address and route them between segments using multicast routing. The remote network would need to have a box that would NAT them back also. Does anyone think this would work? I haven't looked too much into it or tried it yet.