Specify NAT methods
You cannot change the NAT method while Teku is running. To change the NAT method restart the node with the
UPNP to quickly allow inbound peer connections without manual router configuration. Use UPnP in home or small office environments where a wireless router or modem provides NAT isolation.
UPnP automatically detects if a node is running in a UPnP environment and provides port forwarding. UPnP might introduce delays during node startup, especially on networks without a UPnP gateway device.
UPnP support is often disabled by default in networking firmware. If disabled by default, you must explicitly enable UPnP support.
Manually configure your firewall to allow external hosts to create inbound connections to Teku.