Network settings

OpenSearch uses HTTP settings to configure communication with external clients through the REST API and transport settings for internal node-to-node communication within OpenSearch.

To learn more about static and dynamic settings, see Configuring OpenSearch.

OpenSearch supports the following common network settings:

• network.host (Static, list): Binds an OpenSearch node to an address. Use 0.0.0.0 to include all available network interfaces, or specify an IP address assigned to a specific interface. The network.host setting is a combination of network.bind_host and network.publish_host if they are the same value. An alternative to network.host is to configure network.bind_host and network.publish_host separately as needed. See Advanced network settings.

• http.port (Static, single value or range): Binds an OpenSearch node to a custom port or a range of ports for HTTP communication. You can specify an address or a range of addresses. Default is 9200-9300.

• transport.port (Static, single value or range): Binds an OpenSearch node to a custom port for communication between nodes. You can specify an address or a range of addresses. Default is 9300-9400.

Advanced network settings

OpenSearch supports the following advanced network settings:

• network.bind_host (Static, list): Binds an OpenSearch node to an address or addresses for incoming connections. Default is the value in network.host.

• network.publish_host (Static, list): Specifies an address or addresses that an OpenSearch node publishes to other nodes in the cluster so that they can connect to it.

Advanced HTTP settings

OpenSearch supports the following advanced network settings for HTTP communication:

• http.host (Static, list): Sets the address of an OpenSearch node for HTTP communication. The http.host setting is a combination of http.bind_host and http.publish_host if they are the same value. An alternative to http.host is to configure http.bind_host and http.publish_host separately as needed.

• http.bind_host (Static, list): Specifies an address or addresses to which an OpenSearch node binds to listen for incoming HTTP connections.

• http.publish_host (Static, list): Specifies an address or addresses that an OpenSearch node publishes to other nodes for HTTP communication.

• http.compression (Static, Boolean): Enables support for compression using Accept-Encoding when applicable. When HTTPS is enabled, the default is false, otherwise, the default is true. Disabling compression for HTTPS helps mitigate potential security risks, such as BREACH attacks. To enable compression for HTTPS traffic, explicitly set http.compression to true.

Advanced transport settings

OpenSearch supports the following advanced network settings for transport communication:

• transport.host (Static, list): Sets the address of an OpenSearch node for transport communication. The transport.host setting is a combination of transport.bind_host and transport.publish_host if they are the same value. An alternative to transport.host is to configure transport.bind_host and transport.publish_host separately as needed.

• transport.bind_host (Static, list): Specifies an address or addresses to which an OpenSearch node binds to listen for incoming transport connections.

• transport.publish_host (Static, list): Specifies an address or addresses that an OpenSearch node publishes to other nodes for transport communication.

Selecting the transport

The default OpenSearch transport is provided by the transport-netty4 module and uses the Netty 4 engine for both internal TCP-based communication between nodes in the cluster and external HTTP-based communication with clients. This communication is fully asynchronous and non-blocking. However, there are other transport plugins available that can be used interchangeably: