Port 139 — NetBIOS Session

Q: What is Harbour 139 for?.Windows sharing. The protocol or service generally associated is NetBIOS Session.Transport ProtocolTCPSafety precautionsPrefer direct SMB to 445 and disable SMBv1.Should we open this port in the Burt?

Only if a service is actually needed l, use it. Apply the principle of any privilege: limit the authorized sources, destinations and interfaces, and then log connections when relevant.

Q: How do I check this port?

Test-NetConnection SERVER -Port 139Under Linux, you can use nc -vz SERVER 139.

TopicWindows Server →

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Port139

TransportTCP

ServiceNetBIOS Session

Port 139TCP

SMB historical sharing via NetBIOS.

What is Harbour 139 for?.

Windows sharing. The protocol or service generally associated is NetBIOS Session.

Transport Protocol

TCP

Safety precautions

Prefer direct SMB to 445 and disable SMBv1.

Should we open this port in the firewall?

Only if a service is actually needed the use it. Apply the principle of any privilege: limit the authorized sources, destinations and interfaces, and then log connections when relevant.

How do I check this port?

Test-NetConnection SERVER -Port 139

Under Linux, you can use nc -vz SERVER 139.

Port/service associations are common conventions. An application can be configured on another port.