Hi, I'm the original poster (Elad Tsur), you can post my name in the version history.

Swapper should see what the IP ve get from other clients (the Remote-IP header, and ofcourse to generate this header too), and advertise this as its IP *even if it is behind a firewall). Some clients (noteably Gnucleus and Morpheus) simply ignore hosts with internal IPs or 0.0.0.0 IP), and thus firewalled users don't get many hits.