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Configure ports

To enable communication you must expose Besu ports appropriately. The following shows an example port configuration for a Besu node on AWS.

Port Configuration

When running Besu from the Docker image, expose ports.

info

If your nodes are running in AWS, ensure you have appropriate SecurityGroups to allow access to the required ports.

tip

Besu supports UPnP for home or small office environments where a wireless router or modem provides NAT isolation.

P2P networking​

To enable peer discovery, the P2P UDP port must be open for inbound connections. By default, that UDP port is the same as the TCP P2P port set with --p2p-port (and --p2p-port-ipv6 for dual-stack).

To bind discovery on a different UDP port, set --p2p-discovery-port (and --p2p-discovery-port-ipv6 for dual-stack). This is useful when the host maps TCP and UDP separately, for example, in Kubernetes.

When the TCP and UDP ports differ, the advertised enode URL includes ?discport=<udp-port>. For example:

besu --p2p-port=30303 --p2p-discovery-port=30301

Options that end in ipv6 configure dual-stack networking.

We also recommend opening the P2P TCP port for inbound connections. This is not strictly required because Besu attempts to open outbound TCP connections. But if no nodes on the network are accepting inbound TCP connections, nodes cannot communicate.

To specify the P2P host, set --p2p-host (and --p2p-host-ipv6 for dual-stack).

By default, peer discovery listens on all available network interfaces. If the device Besu is running on must bind to a specific network interface, specify the interface using --p2p-interface (and --p2p-interface-ipv6 for dual-stack).

JSON-RPC API​

To enable access to the JSON-RPC API, open the HTTP JSON-RPC and WebSockets JSON-RPC ports to the intended users of the JSON-RPC API on TCP.

Specify the HTTP and WebSockets JSON-RPC ports using the --rpc-http-port and --rpc-ws-port options. The defaults are 8545 and 8546.

Metrics​

To enable Prometheus to access Besu, open the metrics port or metrics push port to Prometheus or the Prometheus push gateway on TCP.

Specify the ports for Prometheus and Prometheus push gateway using the --metrics-port and --metrics-push-port options. The defaults are 9545 and 9001.