GRC | Port Authority, for Internet Port 139

Port Authority Edition – Internet Vulnerability Profiling
by Steve Gibson, Gibson Research Corporation.

Goto Port 138

Probe Port 139


Enter Port: 0-65535

Goto Port 140

Port Authority Database

Port 139

Name:	netbios-ssn
Purpose:	NETBIOS Session Service
Description:	TCP NetBIOS connections are made over this port, usually with Windows machines but also with any other system running Samba (SMB). These TCP connections form "NetBIOS sessions" to support connection oriented file sharing activities.
Related Ports:	137, 138, 445

Background and Additional Information:

This is the third port of the original "NetBIOS trio" used by the first Windows operating systems (up through Windows NT) in support of file sharing.

For additional information about this trio of Internet ports, please see the "Background and Additional Information" for the first port of the trio, port 137.

Trojan Sightings: Chode, God Message worm, Msinit, Netlog, Network, Qaz, Sadmind, SMB Relay

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