Network address translation

Network address translation (NAT) is a method of mapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device.^[1] The technique was originally used to bypass the need to assign a new address to every host when a network was moved, or when the upstream Internet service provider was replaced, but could not route the network's address space. It has become a popular and essential tool in conserving global address space in the face of IPv4 address exhaustion. One Internet-routable IP address of a NAT gateway can be used for an entire private network.^[2]

As network address translation modifies the IP address information in packets, NAT implementations may vary in their specific behavior in various addressing cases and their effect on network traffic. The specifics of NAT behavior are not commonly documented by vendors of equipment containing NAT implementations.^[2]

^ Network Protocols Handbook (2 ed.). Javvin Technologies Inc. 2005. p. 27. ISBN 9780974094526. Retrieved 2014-09-16.
^ ^a ^b François Audet; Cullen Jennings (January 2007). Network Address Translation (NAT) Behavioral Requirements for Unicast UDP. IETF. doi:10.17487/RFC4787. RFC 4787.

[1] Network Protocols Handbook (2 ed.). Javvin Technologies Inc. 2005. p. 27. ISBN 9780974094526. Retrieved 2014-09-16.

[rfc4787-2] François Audet; Cullen Jennings (January 2007). Network Address Translation (NAT) Behavioral Requirements for Unicast UDP. IETF. doi:10.17487/RFC4787. RFC 4787.

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