Port 2181 supports Apache ZooKeeper and eforward (UDP reference coverage) across distinct transports. Review each protocol before writing firewall or monitoring policy.
Default ZooKeeper client connection endpoint.
Apache ZooKeeper endpoints in environments where this service is explicitly configured.
Cluster internal
Keep cluster-internal, enable authentication and TLS where supported, and restrict administrative commands.
eforward (UDP reference coverage) is documented as a network service convention for port 2181 over UDP.
Use this reference entry when identifying or validating systems documented to use 2181/UDP.
Varies
Confirm the listening process and current vendor documentation before permitting traffic; a listed convention does not prove the active service or its security posture.