Port Control Protocol makes it possible to reach network equipments from an outside of their local networks behind a NAT. Usually this requires manual configuration of port forwarding at the network gateway, or application level workarounds. PCP allows the deployed equipment and applications to create explicit mappings between an external IP address, protocol and port, and an internal IP address, protocol and port. These mappings are required for successful inbound communications destined to machines located behind a NAT or a firewall.
RFC6887
RFC6887
RFC6887
RFC7220
RFC7225
Amplification
Information Leakage