Network address translation

In computer networking, Network Address Translation (NAT, also known as Network Masquerading, Native Address Translation or IP Masquerading) is a technique of transceiving network traffic through a router that involves re-writing the source and/or destination IP addresses and usually also the TCP/UDP port numbers of IP packets as they pass through. Checksums (both IP and TCP/UDP) must also be rewritten to take account of the changes. Most systems using NAT do so in order to enable multiple hosts on a private network to access the Internet using a single public IP address (see gateway). Many network administrators find NAT a convenient technique and use it widely. Nonetheless, NAT can introduce complications in communication between hosts and may have a performance impact.
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<networking> (NAT, or Network Address Translator, Virtual LAN) A hardware device currently being developed and used to extend the Internet addresses already in use. NAT has been suggested as an alternative to adopting IPv6 (IPng). It allows duplicate IP addresses to be used within a corporation and unique addresses outside.
["NATs are next naughty Internet issue", Christine Hudgins-Bonafield cbonafield@nwc.com, in "Network Computing", March 1, 1995].
(1995-04-01)