What port does NBNS use?

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Multiple Choice

What port does NBNS use?

Explanation:
NetBIOS Name Service (NBNS) is the component of NetBIOS over TCP/IP responsible for mapping NetBIOS names to IP addresses on a local network. The standard port for this name resolution service is UDP 137. When a host needs to resolve or register a NetBIOS name, it sends queries to port 137 and receives responses on the same port. The other ports shown are for different services: DNS uses port 53 (both UDP and TCP), NetBIOS has other functions on different ports—Datagram Service on UDP 138 and Session Service on TCP 139. Those are not NBNS name queries, which is why UDP 137 is the correct port for NBNS.

NetBIOS Name Service (NBNS) is the component of NetBIOS over TCP/IP responsible for mapping NetBIOS names to IP addresses on a local network. The standard port for this name resolution service is UDP 137. When a host needs to resolve or register a NetBIOS name, it sends queries to port 137 and receives responses on the same port.

The other ports shown are for different services: DNS uses port 53 (both UDP and TCP), NetBIOS has other functions on different ports—Datagram Service on UDP 138 and Session Service on TCP 139. Those are not NBNS name queries, which is why UDP 137 is the correct port for NBNS.

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