besu/docs/Configuring-Pantheon/Networking.md

description: Pantheon networking is about P2P discovery and communication between peers and access to the JSON RPC APIs
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# Networking

Pantheon uses the network to find and connect to peers. 

## Port Configuration 

Ports must be exposed appropriately to enable communication. An example port configuration for a Pantheon node on AWS is: 
                                     
![Port Configuration](../images/PortConfiguration.png)

When running Pantheon from the [Docker image](../Getting-Started/Run-Docker-Image.md), [expose ports](../Getting-Started/Run-Docker-Image.md#exposing-ports). 

### P2P Networking 

To enable peer discovery, the P2P UDP port must be open for inbound connections.

We also recommended opening the P2P TCP port for inbound connections. This is not strictly required because 
Pantheon attempts to initiate outbound TCP connections. However, if no nodes on the network are accepting inbound TCP 
connections, nodes cannot communicate.

The P2P port is specified by the [`--p2p-port`](../Reference/Pantheon-CLI-Syntax.md#p2p-port) option. 
The default is `30303`. 

### JSON-RPC API 

To enable access to the [JSON-RPC API](../JSON-RPC-API/JSON-RPC-API.md), open the HTTP JSON-RPC and WebSockets JSON-RPC ports to the intended users 
of the JSON-RPC API on TCP. 

The [`--rpc-http-port`](../Reference/Pantheon-CLI-Syntax.md#rpc-http-port) and [`--rpc-ws-port`](../Reference/Pantheon-CLI-Syntax.md#rpc-ws-port) 
options specify the HTTP and WebSockets JSON-RPC ports. The defaults are `8545` and `8546`.  

### Metrics 

To enable [Prometheus to access Pantheon](../Using-Pantheon/Debugging.md#monitor-node-performance-using-prometheus), 
open the metrics port or metrics push port to Prometheus or the Prometheus push gateway on TCP.  

The [`--metrics-port`](../Reference/Pantheon-CLI-Syntax.md#metrics-port) and [`--metrics-push-port`](../Reference/Pantheon-CLI-Syntax.md#metrics-push-port) 
options specify the ports for Prometheus and Prometheus push gateway. The defaults are `9545` and `9001`.  

## Node Connections

The default logging configuration does not list node connection and disconnection messages.  

To enable listing of node connection and disconnection messages, specify the 
[`--logging`](../Reference/Pantheon-CLI-Syntax.md#logging) command line option `--logging=DEBUG`.
For more verbosity, specify `--logging=TRACE`.  

The console logs connection and disconnection events when the log level is `DEBUG` or higher.  
If `Successfully accepted connection from ...` is displayed, connections are getting through the firewalls. 

!!! example "Example log output"
    `2018-10-16 12:37:35.479-04:00 | nioEventLoopGroup-3-1 | INFO  | NettyP2PNetwork | Successfully accepted connection from 0xa979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c`
 
## Limiting Peers

Limiting peers reduces the bandwidth used by Pantheon. It also reduces the CPU time and disk access 
used to manage and respond to peers.  
 
Use the [`--max-peers`](../Reference/Pantheon-CLI-Syntax.md#max-peers) command line option to reduce 
the maximum number of peers. The default is 25.

## No Discovery

The [`--discovery-enabled`](../Reference/Pantheon-CLI-Syntax.md#discovery-enabled) command line option 
can be used to disable P2P peer discovery.
Set this option to `false` if you are running a test node or a test network with fixed nodes.

Use the [`admin_addPeer`](../Reference/JSON-RPC-API-Methods.md#admin_addpeer) JSON-RPC method to add peers when 
[`--discovery-enabled`](../Reference/Pantheon-CLI-Syntax.md#discovery-enabled) is set to false. 

## Monitoring Peer Connections

Use the [`debug_metrics`](../Reference/JSON-RPC-API-Methods.md#debug_metrics) JSON-RPC API method 
to obtain information about peer connections.