Internal communication

EventStoreDB nodes normally need internal networking only when running in a cluster. The internal network is where cluster communications runs, while the external interfaces is where client communications runs.

Separating internal and external communication allows to balance the network traffic. Cluster nodes communicate extensively and replicate all the data between the nodes. When you use a separate network for that, the external clients won't be affected by the replication traffic.

Network separation also allows more secure setups. For example, you might only enable the management interface and stats to only be accessible internally.

You configure the internal TCP and HTTP ports in the same way as the external. All internal communications for the cluster happen over these interfaces. Elections and internal gossip happen over HTTP. Replication and forwarding of client requests happens over the TCP channel.


By default, EventStoreDB binds its internal networking on the loopback interface only ( You can change this behaviour and either tell EventStoreDB to listen on all interfaces or explicitly specify which internal IP address the server should use. To do that set the IntIp to or the IP address of the network interface.

Command line--int-ip
Environment variableEVENTSTORE_Int_IP

Default: (loopback).

For example, adding ExtIp= to the eventstore.conf file will instruct EventStoreDB to allow internal communication on all interfaces.


EventStoreDB only uses two ports to communicate with other cluster nodes.

The first port is the internal HTTP port, and the default value is 2112. EventStoreDB uses this port for the cluster gossip protocol.

The second port used is the TCP interface for all other communication between cluster nodes, such as replication, and the default for the port is 1112.

You should ensure that cluster nodes are able to reach each other using these ports.

Use the settings described below to change default internal ports.

Command line--int-tcp-port
Environment variableEVENTSTORE_INT_TCP_PORT

Default: 1112

Command line--int-http-port
Environment variableEVENTSTORE_INT_HTTP_PORT

Default: 2112