---
layout: default
title: Network settings
parent: Configuring OpenSearch
nav_order: 20
---

# 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]({{site.url}}{{site.baseurl}}/install-and-configure/configuring-opensearch/index/).

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](#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](https://netty.io/) 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:

Plugin | Description
:---------- | :--------
`transport-nio`    | The OpenSearch transport based on Java NIO. <br> Installation: `./bin/opensearch-plugin install transport-nio` <br> Configuration (using `opensearch.yml`): <br> `transport.type: nio-transport` <br> `http.type: nio-http-transport`
`transport-reactor-netty4`    | The OpenSearch HTTP transport based on [Project Reactor](https://github.com/reactor/reactor-netty) and Netty 4 (**experimental**) <br> Installation: `./bin/opensearch-plugin install transport-reactor-netty4` <br> Configuration (using `opensearch.yml`): <br> `http.type: reactor-netty4`