The NAT Port Mapping Protocol (NAT-PMP) is a network protocol for establishing network address translation (NAT) settings and port forwarding configurations automatically without user effort. The protocol automatically determines the external IPv4 address of a NAT gateway, and provides means for an application to communicate the parameters for communication to peers. NAT-PMP was introduced in 2005 by Apple 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 (RFC) by the Internet Engineering Task Force (IETF) in .