NBSS

NBSS is an acronym that can refer to several meanings, but it is most widely known in information technology as NetBIOS Session Service, a component of NetBIOS over TCP/IP (NBT).

NetBIOS Session Service provides the connection-oriented portion of NetBIOS communications. After NetBIOS names are resolved to network addresses, NBSS establishes a session between two NetBIOS names, negotiates session parameters, and carries NetBIOS messages and related traffic (such as SMB) within a defined session. The service is typically carried over TCP, with legacy Windows networks commonly using port 139. In modern deployments, SMB traffic may be carried directly over TCP port 445, with NetBIOS support often limited or disabled for security reasons.

Security and relevance: NetBIOS over TCP/IP, including NBSS, has been associated with a range of security concerns, such as exposure to worms and misconfigurations. As a result, many networks block or disable NBSS/NetBIOS traffic in firewalls and use newer protocols or direct SMB transport to minimize risk. Despite its decline in new installations, NBSS remains present in some legacy environments and requires careful management in mixed networks.

Other uses: In addition to computing, NBSS is an acronym used by various organizations and projects, with meanings that vary by country and field. The exact interpretation depends on context, and there is no single universally applicable alternative meaning. A disambiguation would require additional context such as geography or domain.