It should be noted that there are two main protocols for mapping ports, UPnP and Port Control Protocol (or NAT-PMP, which is PCP version 0). UPnP is dramatical

It should be noted that there are two main protocols for mapping ports, UPnP and Port Control Protocol (or NAT-PMP, which is PCP version 0). UPnP is dramatically more complicated and has correspondingly more implementation bugs. If you need to have something enabled on your router for mapping ports, use Port Control Protocol and disable UPnP.