The main source of slavery in this part of the world in the Middle Ages was indebtedness. In China, impoverished peasants frequently sold members of their own families into slavery, and throughout the entire medieval period criminals or members of their families became slaves of the state.
Nonetheless, NAT can introduce complications in communication between hosts.     * NAT(Network Address Translation) is most commonly used by broadband routers. NAT allows the router to assign non-publically routable IP addresses to the computers on the network.
STUN (Simple Traversal of UDP through NAT) Simple Traversal of UDP through NAT (STUN) is a protocol that governs the exchange of data over a User Datagram Protocol (UDP) connection by communications devices operating behind a Network Address Translator (NAT) or firewall. The main objective of STUN is to overcome some of the problems associated with the lack of standardized behaviors in NATs.