# Functions
Any returns a port mapper that tries to discover any supported mechanism on the local network.
Map adds a port mapping on m and keeps it alive until c is closed.
Parse parses a NAT interface description.
PMP returns a port mapper that uses NAT-PMP.
RequestAutoIP returns external ip address of a host machine.
UPnP returns a port mapper that uses UPnP.
# Interfaces
An implementation of nat.Interface can map local ports to ports accessible from the Internet.