FreshTomato Wiki

UPnP (Universal Plug and Play) is a controversial protocol which allows fully dynamic (automatic) port mapping from LAN IP addresses onto the Internet. UPnP has been heavily criticized for its poor security. With this protocol, each program that uses the network maps its own ports automatically. In the screenshot below, the WhatsApp application has mapped certain ports on FreshTomato's WAN IP/Interface.

UPnP is the original implementation of this dynamic port-mapping protocol. NAT-PMP (NAT Port Mapping Protocol) is a newer, enhanced version of UPnP, designed for better compatibility with NAT routing. NAT-PMP is part of Apple's Bonjour protocol, and is often used for streaming iTunes and other media.

If you use dynamic port forwarding, you'll probably want to enable both protocols to maintain backward compatibility.

Enable UPnP: Enable and Disable UPnP.

Enable NAT-PMP: Enable/Disable NAT-PMP.

Inactive Rule Cleaning: This sets the timeout period to remove rules counted from the last time traffic was flowing.

Cleaning Interval: This specifies how often the cleaning sub-process is executed.

Cleaning Threshold: This sets the maximum number of rules to be removed by an Interval.

Secure Mode: Allows only the “owner LAN IP” to trigger its own mapping/unmapping. In other words, the client could only map an incoming port to its own IP address, not to another IP address.

Enable on: This allows you to enable UPnp/NATPMP only on certain VLANs.

Show in My Network Places: If enabled, this makes FreshTomato appear as a gateway in Windows' browsable LAN network (WORKGROUP or HOMEGROUP).

Miniupnpd custom config: In this field, you can enter custom configuration options not available in the web interface. In the image below, UPnP requests/mappings are denied for a specific IP address only.