nat-traverse - 0.7-2 main

nat-traverse establishes connections between nodes which are
behind NAT gateways, i.e. hosts which do not have public IP
addresses. Additionally, you can setup a small VPN by using pppd
on top of nat-traverse. nat-traverse does not need an external
server on the Internet, and it isn't necessary to reconfigure
the involved NAT gateways, either. nat-traverse works
out-of-the-box.