NAT Port Mapping Protocol (NAT-PMP) is a

network protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchroni ...

for establishing network address translation (NAT) settings and port forwarding configurations automatically without user effort. The protocol automatically determines the external

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version d ...

address of a NAT gateway, and provides means for an application to communicate the parameters for communication to peers.

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ances ...

introduced NAT-PMP in 2005 by as part of the Bonjour specification, as an alternative to the more common ISO Standard Internet Gateway Device Protocol implemented in many NAT routers. The protocol was published as an informational

Request for Comments A Request for Comments (RFC) is a publication in a series from the principal technical development and standards-setting bodies for the Internet, most prominently the Internet Engineering Task Force (IETF). An RFC is authored by individuals or ...

(RFC) by the

Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and ...

(IETF) in RFC 6886. NAT-PMP runs over the

User Datagram Protocol In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages (transported as datagrams in packets) to other hosts on an Internet Protocol (IP) networ ...

(UDP) and uses

port number In computer networking, a port is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service. At the software level, within an operating system, a port is a logical construct that identifies a specific ...

5351. It has no built-in

authentication Authentication (from ''authentikos'', "real, genuine", from αὐθέντης ''authentes'', "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicat ...

mechanisms because forwarding a port typically does not allow any activity that could not also be achieved using

STUN STUN (Session Traversal Utilities for NAT; originally Simple Traversal of User Datagram Protocol (UDP) through Network Address Translators) is a standardized set of methods, including a network protocol, for traversal of network address transl ...

methods. The benefit of NAT-PMP over STUN is that it does not require a STUN server and a NAT-PMP mapping has a known expiration time, allowing the application to avoid sending inefficient keep-alive packets. NAT-PMP is the predecessor to the Port Control Protocol (PCP).RFC 6887, ''Port Control Protocol (PCP)'', Wing, Cheshire, Boucadair, Penno & Selkirk (April 2013)

References

Apple Inc. services Network protocols Network address translation {{Apple-stub

See also

References