Port 1434 supports SQL Server Browser and ms-sql-m (TCP reference coverage) across distinct transports. Review each protocol before writing firewall or monitoring policy.
Discovers SQL Server named instances and their assigned ports.
Clients locating named SQL Server instances without a port specified in the connection string.
Client to server
Disable when unnecessary and restrict discovery to trusted application or administration networks.
ms-sql-m (TCP reference coverage) is documented as a network service convention for port 1434 over TCP.
Use this reference entry when identifying or validating systems documented to use 1434/TCP.
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.