Troubleshoot port forwarding

No router is found

Confirm UPnP or NAT-PMP is enabled in the router settings and that the server host shares the router's local network. If multicast discovery is blocked, set router.upnp_search to the router's address and port. For NAT-PMP, set router.nat_pmp_gateway to the gateway address when automatic local-address probing cannot find it.

Containers and networks with multiple routers can hide the gateway. Ensure the container has the network access required to send and receive router discovery packets.

A mapping is refused or players cannot connect

Check /upnp status for the router address and each port's state. A router with a non-public internet-side address, including carrier-grade NAT, cannot provide an inbound route. A machine that already has a public address does not need a mapping. Some routers are deliberately refused because they do not support UPnP or NAT-PMP safely; create the port rules manually in that case.

Confirm the Java and Bedrock configured ports match the listeners and protocols. Java uses TCP; Bedrock uses UDP. The router's mapping does not replace host firewall rules.

A plugin's requested port closes

Check that plugins.allow_requests is enabled and that the requesting plugin stays active. Each plugin can keep at most plugins.max_requests_per_plugin mappings open. Requests expire after five minutes without a refresh and close when the requesting plugin stops its watcher or the server stops.

Use /upnp reload after editing the config. If the plugin reports that its router is unsupported, no mapping was opened; forward the port manually instead.