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Couchbase Server Ports

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      Couchbase Server uses multiple TCP ports to facilitate communication between server components, as well as with Couchbase clients. These ports must be open for Couchbase Server to operate correctly.

      Ports Overview

      This page describes the TCP ports that are used by Couchbase Server for network communication. Some ports, such as those used for cluster management, are required to be open on every node because they are essential to how Couchbase Server communicates with itself. Other ports are used by individual Couchbase Services, and are only required to be open on the nodes where those services are running.

      Couchbase Server uses a default set of port numbers for all ports that it requires. The Couchbase Cluster Manager on each node is responsible for port management, and will open and close these ports on the host as necessary, as well as automatically switch to using encrypted ports if the cluster is configured to use TLS. Most port numbers can be remapped to fit the requirements of your network environment, but some port numbers cannot be changed.

      If other software on the same host is using any of the ports that are required by Couchbase Server, then Couchbase Server will not function properly and may fail to start. Refer to Port Availability below.

      Ephemeral Ports

      An ephemeral port is one temporarily allocated by a server’s operating system, as the source for an outgoing communication. Each operating system provides a default range of port numbers that can be assigned to ephemeral ports, when necessary. For Linux distributions, the typical range is 32768-61000. Couchbase Server relies on the full default range provided by each operating system: therefore, the default range should not be reduced by the administrator; since the resulting lack of ephemeral ports may result in outgoing communications using well-known ports instead (for example, 8091); thereby preventing Couchbase-Server processes from binding to the well-known ports to which they are assigned.

      Couchbase Server Communication Paths

      Couchbase Server components and services connect to each port over one or more communication paths. These paths are defined as:

      • Node-local: A Couchbase service running on a node connects to the port on localhost, and communication happens entirely within the node itself.

      • Node-to-node: A Couchbase service connects to the port on other nodes in the cluster.

      • Client-to-node: A Couchbase client, such as an application using the Couchbase SDK, connects to the port on the node that it requires access to.

      • XDCR (cluster-to-cluster): A source node connects to the port on a destination node of another cluster as part of an XDCR replication stream. (This is very similar to the client-to-node communication path.)

        There are two versions of XDCR that each use their own protocol: Version 1 (CAPI), which uses the REST protocol, and Version 2 (XMEM), which uses the Memcached Binary protocol. The default is Version 2, and it should be noted that each version requires a different set of ports. Refer to XDCR Advanced Settings for more information about XDCR versions.

      Each communication path used by a required port must remain open and unblocked by firewalls or other such mechanisms.

      Port Availability

      Neither the Cluster Manager nor any of the Couchbase Services will start if unable to listen on all required ports. Note that the cluster manager and all services attempt to bind to required ports using the IP address family that the Couchbase Server cluster is configured to use (see Manage Address Families). Therefore, if the Couchbase Server cluster is configured to use IPv6, the cluster manager and all services attempt to bind to required ports using IPv6; and if the cluster is configured to use IPv4, the cluster manager and all services attempt to bind to required ports using IPv4. If the cluster manager or service is unable to bind to one or more required ports using the configured IP address family, it will not start.

      Refer to the Detailed Port Description, below, for a list of the ports required by each service.

      Ports Listed by Communication Path

      The following table lists all port numbers, grouped by category of communication path.

      Table 1. All Couchbase Server Ports, Listed by Communication Path
      Communication Path Default Ports

      Node-local only

      Unencrypted: 9119, 9998, 11213, 21200, 21300

      Encrypted: 21250 [1], 21350 [2]

      Node-to-node

      Unencrypted: 4369, 8091-8094, 9100-9105, 9110-9118, 9120-9122, 9130, 9999, 11209-11210, 21100

      Encrypted: 9999, 11206, 11207, 18091-18094, 19102, 19130, 21150

      Client-to-node

      Unencrypted: 8091-8097, 9123, 9140 [3], 11210

      Encrypted: 11207, 18091-18095, 18096, 18097

      XDCR (cluster-to-cluster)

      • Version 1 (CAPI)

        • Unencrypted: 8091, 8092

      • Version 2 (XMEM)

        • Unencrypted: 8091, 8092, 11210

        • Encrypted: 11207, 18091, 18092

      If enforcing TLS encryption, these ports may be blocked outside of a Couchbase Server cluster but need to remain open between nodes.
      Certain support and diagnostic requests may run against ports other than the administration port (8091). These are expected to execute locally on a node and so do not require external access.

      Detailed Port Description

      The following table contains a detailed description of each port used by Couchbase Server.

      Table 2. All Couchbase Server Ports, Listed by Service
      Port name Default port number
      (un / encrypted)
      Description Node-to-node Client-to-node XDCR (cluster-to-cluster)

      epmd [4]

      4369

      Erlang Port Mapper Daemon

      Yes

      No

      No

      rest_port / ssl_rest_port

      8091 / 18091

      Cluster administration REST/HTTP traffic, including Couchbase Web Console

      Yes

      Yes

      Version 1 & 2

      capi_port / ssl_capi_port

      8092 / 18092

      Views and XDCR access

      Yes

      Yes

      Version 1 & 2

      query_port / ssl_query_port

      8093 / 18093

      Query service REST/HTTP traffic

      Yes

      Yes

      No

      fts_http_port / fts_ssl_port

      8094 / 18094

      Search Service REST/HTTP traffic

      Yes

      Yes

      No

      cbas_http_port / cbas_ssl_port

      8095 / 18095

      Analytics service REST/HTTP traffic

      No

      Yes

      No

      eventing_http_port / eventing_ssl_port

      8096 / 18096

      Eventing service REST/HTTP traffic

      No

      Yes

      No

      backup_http_port / backup_ssl_port

      8097 / 18097

      Backup service REST/HTTP traffic

      No

      Yes

      No

      indexer_admin_port

      9100

      Indexer service

      Yes

      No

      No

      indexer_scan_port

      9101

      Indexer service

      Yes

      No

      No

      indexer_http_port

      9102

      Indexer service

      Yes

      No

      No

      indexer_https_port

      19102

      Indexer service

      Yes

      No

      No

      indexer_stinit_port

      9103

      Indexer service

      Yes

      No

      No

      indexer_stcatchup_port

      9104

      Indexer service

      Yes

      No

      No

      indexer_stmaint_port

      9105

      Indexer service

      Yes

      No

      No

      cbas_admin_port

      9110

      Analytics service

      Yes

      No

      No

      cbas_cc_http_port

      9111

      Analytics service

      Yes

      No

      No

      cbas_cc_cluster_port

      9112

      Analytics service

      Yes

      No

      No

      cbas_cc_client_port

      9113

      Analytics service

      Yes

      No

      No

      cbas_console_port

      9114

      Analytics service

      Yes

      No

      No

      cbas_cluster_port

      9115

      Analytics service

      Yes

      No

      No

      cbas_data_port

      9116

      Analytics service

      Yes

      No

      No

      cbas_result_port

      9117

      Analytics service

      Yes

      No

      No

      cbas_messaging_port

      9118

      Analytics service

      Yes

      No

      No

      cbas_auth_port

      9119

      Analytics service

      (node-local only)

      No

      No

      No

      cbas_replication_port

      9120

      Analytics service

      Yes

      No

      No

      cbas_metadata_port

      9121

      Analytics service

      Yes

      No

      No

      cbas_metadata_callback_port

      9122

      Analytics service

      Yes

      No

      No

      prometheus_http_port

      9123

      Cluster management traffic and communication

      No

      Yes

      No

      backup_grpc_port

      9124

      Backup Service gRPC

      Yes

      No

      No

      fts_grpc_port / fts_grpc_ssl_port

      9130 / 19130

      Search Service gRPC port used for scatter-gather operations between FTS nodes

      Yes

      No

      No

      eventing_debug_port [3]

      9140

      Eventing Service Debugger

      No

      Yes

      No

      xdcr_rest_port

      9998

      XDCR REST port

      (node-local only)

      No

      No

      No

      projector_port

      9999 / 9999

      Indexer service

      Yes

      No

      No

      memcached_dedicated_port / memcached_dedicated_ssl_port

      11209 / 11206

      Data Service and ns_server. Used for important control-commands; e.g. creation of buckets and vBuckets, and compaction.

      Yes

      No

      No

      memcached_port / memcached_ssl_port

      11210 / 11207

      Data Service

      Yes

      Yes

      Version 2

      memcached_prometheus

      11280

      Data Service

      No

      Yes

      No

      Cluster Management Exchange

      21100 / 21150

      Cluster management traffic and communication

      Yes

      No

      No

      Cluster Management Exchange [1]

      21200 / 21250

      Cluster management traffic and communication

      (node-local only)

      No

      No

      No

      Cluster Management Exchange [2]

      21300 / 21350

      Cluster management traffic and communication

      (node-local only)

      No

      No

      No

      Custom Port Mapping

      Most, but not all, port numbers used by Couchbase Server can be remapped from their defaults to fit the requirements of your network environment. Refer to Table 2 for details about default ports and whether or not they can be remapped.

      Changing the port mappings will require a reset and reconfiguration of any Couchbase Server node.

      Changing port mappings should only be done at the time of initial node/cluster setup as the required reset and reconfiguration will also purge all data on the node.
      To Change Port Mapping
      1. Install Couchbase Server.

      2. Stop the Couchbase Server service.

      3. For most ports, you’ll need to edit the Couchbase Server static_config file. (This will be wherever you put the path to /couchbase/etc/couchbase/static_config in multi-node installations.)

        vi /opt/couchbase/etc/couchbase/static_config

        If you’re remapping the CAPI port (8092 / 18092) you’ll need to edit the /opt/couchbase/etc/couchdb/default.d/capi.ini file and replace 8092 with the new port number.

      4. Add each custom port map entry on its own line, using the following format (enclosed in braces and terminated by a period):

        {port-name, port-number}.

        For example, to change the REST API port from 8091 to 9000, you would add the following line:

        {rest_port, 9000}.

        Once you’ve added all of your custom port mappings, save the file and close your text editor.

      5. If Couchbase Server was previously configured, you’ll need to delete the /opt/couchbase/var/lib/couchbase/config/config.dat file and files in the /opt/couchbase/var/lib/couchbase/config/chronicle/ directory to remove the old configuration.

        rm -rf /opt/couchbase/var/lib/couchbase/config/config.dat
        rm -rf /opt/couchbase/var/lib/couchbase/config/chronicle/*
      6. Start Couchbase Server.

      Any ports not given a custom mapping in the static_config file will continue to be assigned their defaults, which are listed in Table 2.


      1. The Cluster Management Exchange encrypted port 21250 is not currently used, but is reserved for future use.
      2. The Cluster Management Exchange encrypted port 21350 is not currently used, but is reserved for future use.
      3. The Eventing Service Debugger port eventing_debug_port (9140) is an internal port and is not supported for external access outside of the cluster. You should only use this port in your development environments.
      4. This port cannot be remapped.