What is NetBIOS 139?
What is NetBIOS 139?
Port 139 is utilized by NetBIOS Session service. Enabling NetBIOS services provide access to shared resources like files and printers not only to your network computers but also to anyone across the internet. Therefore it is advisable to block port 139 in the Firewall.
What is port 139 primarily used for?
Port 139 is used by SMB dialects that communicate over NetBIOS. It’s a transport layer protocol designed to use in Windows operating systems over a network.
What is the port name for 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 |
Why is port 139 open?
If you are on Windows-based network that is running NetBios, it is perfectly normal to have port 139 open in order to facilitate that protocol. If you are not on a network using NetBios, there is no reason to have that port open.
Is port 139 insecure?
Port 139 is used for File and Printer Sharing but happens to be the single most dangerous Port on the Internet. This is so because it leaves the hard disk of a user exposed to hackers.
Does smb2 use port 139?
SMB has always been a network file sharing protocol. As such, SMB requires network ports on a computer or server to enable communication to other systems. SMB uses either IP port 139 or 445. Port 445: Later versions of SMB (after Windows 2000) began to use port 445 on top of a TCP stack.
How do I check if port 139 is open?
For test the port 139, please try use the IP address of the server, NetBIOS or FQDN. You can use the telnet command or PortQuery tools.