Network Address Translation


Network Address Translation

(networking)(NAT, or Network Address Translator, Virtual LAN)A technique in which a router or firewall rewrites thesource and/or destination Internet addresses in a packet asit passes through, typically to allow multiple hosts toconnect to the Internet via a single external IP address.NAT keeps track of outbound connections and distributesincoming packets to the correct machine.

NAT is an alternative to adopting IPv6 (IPng). It allowsthe same IP addresses (10.x.x.x is the conventional range) tobe used on many private local networks while requiring onlyone of the increasingly scarce public addresses to beallocated to each private network.

NAT does not however allow an external service to initiate aTCP connection to an internal host, nor does it supportstateless protocols based on UDP well unless the routersoftware has extensions to support each specific protocol.