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Included in the protocol is a method for retrieving the external IPv4 address of a NAT gateway, thus allowing a client to make its external IPv4 address IPv4 address and port known to peers that who may wish to communicate with it.
NAT-PMP uses UDP port number 5350 - on the client, and 5351 on the server side.
There are two interface types for PMP: internal (the one local clients are connected to) and external (the one the Internet is connected to). A router may only have one active external interface with a 'public' IP address on it, and as many internal interfaces as needed, all with source-NATted 'internal' IP addresses. The protocol works by creating dynamic NAT entries.
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| Property | Description |
|---|---|
| interface (string; Default: ) | Interface name on which PMP will be running on |
| type (external | internal; Default: no) | PMP interface type:
|
| forced-ip (Ip; Default: ) | Allow specifying what public IP to use if the external interface has more than one IP available. |
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