In a multi-node Elasticsearch cluster, transport.port selects the port nodes use to communicate with one another. It is separate from the HTTP port used by REST clients; transport communication uses 9300 by default, while HTTP uses 9200 by default. section 14.2 section 14.7
Use transport.port when configuring the network boundary between Elasticsearch nodes:
- Set it in elasticsearch.yml for each node that must use a non-default internal communication port. section 14.5.1
- Keep it distinct from http.port, which controls client access through REST endpoints. section 14.7
- Coordinate the port with network.host, firewall rules, and the rest of the cluster’s network settings. section 14.2
- Manage repeated settings centrally when operating a large cluster, using shared configuration practices or housekeeping automation. section 14.2
Change the internal transport port
In elasticsearch.yml: transport.port: 9901 This changes the port used for node-to-node communication. Clients still use http.port unless that setting is changed separately, and every participating node must use compatible network settings. section 14.5.1 section 14.2
