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Specify the NAT method

Use the --nat-method option to specify the NAT method. Options are: UPNP, KUBERNETES, DOCKER, AUTO, and NONE.

The enode advertised to other nodes during discovery is the external IP address and port. The admin_nodeInfo JSON-RPC API method returns the external address and port for the enode and listenAddr properties.

While Besu is running, the following are not supported:

  • IP address changes
  • Changing NAT methods. To change the NAT method, restart the node with the --nat-method option set.

Auto​

AUTO detects if Besu is running inside a Kubernetes cluster or a Docker container.

  • If Besu is running in a Kubernetes cluster, AUTO sets to KUBERNETES.
  • If Besu is running in a Docker container, AUTO sets to DOCKER.
  • If Besu is not running in Kubernetes or Docker container, AUTO sets to NONE.

AUTO is the default NAT method.

The following log shows an automatic detection failure.

The following log shows an automatic detection failure
INFO  | KubernetesNatManager | Starting kubernetes NAT manager.
DEBUG | KubernetesNatManager | Trying to update information using Kubernetes client SDK.
DEBUG | NatService | Nat manager failed to configure itself automatically due to the following reason Service not found. NONE mode will be used
INFO  | NetworkRunner | Starting Network.
tip

If automatic detection fails, set the IP and ports in NONE mode.

UPnP​

Specify 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.

Use UPNPP2PONLY if you wish to enable UPnP only for p2p traffic.

tip

UPnP support is often disabled by default in networking firmware. If disabled by default, you must explicitly enable UPnP support.

info

When the NAT method is set to UPNP, the advertised port is the same as the listening port.

Kubernetes​

Specify KUBERNETES to explicitly specify Besu is running inside a Kubernetes cluster. Besu automatically detects if it's running inside of a Kubernetes cluster and interacts with Kubernetes APIs as required to determine external IP addresses and exposed ports.

In Kubernetes, the Ingress IP of the load balancer will be used as the external IP for Besu. A load balancer service can map any incoming port to a target port. These mapping rules will be the one retrieved by Besu.

A tutorial to Configure the Nat Manager for Kubernetes is available.

Docker​

Specify DOCKER to explicitly specify Besu is running inside a Docker container. If you specify DOCKER, you advertise the host IP address not the container IP address.

The host IP address is the advertised host specified in the docker run command. If not specified in the docker run command, the advertised host defaults to the values for --p2p-host and --p2p-port.

None​

Specify NONE to explicitly configure the external IP address and ports advertised using:

The P2P and JSON-RPC HTTP hosts and ports are advertised in the net_services method.

tip

When the NAT method is set to NONE, the advertised port is the same as the listening port.