What is netbios-ssn (port 139)

[Y2kCyK]

My norton continuesly giving me popup that someone is trying to access the netbios-ssn (port 139). What that means? If you have any knowledge about it , please share here. Thanks for any help.

[JohnRolandElliott]

from C:\windows\system32\drivers\etc\services


netbios-ns 137/tcp nbname #NETBIOS Name Service
netbios-ns 137/udp nbname #NETBIOS Name Service
netbios-dgm 138/udp nbdatagram #NETBIOS Datagram Service
netbios-ssn 139/tcp nbsession #NETBIOS Session Service


NetBIOS is the protocol on which (among other things) Windows Print/File Sharing is implemented.

[Navman]

About port 139 : This is for the TCP NetBIOS connections, mostly with Windows machines, but also with other systems running Samba. TCP connections form "NetBIOS sessions" to support connection oriented file sharing activities. This is the third port of the original "NetBIOS trio" used by the first Windows operating system to support file sharing.

Source: grc.com

[worm4u]

1. This ink is an article on how to restrict anonymous access. It's for Windows 2000, but I'm pretty sure it'll work on XP.
   Restricting anonymous connections.
   
   
2. Also to make your pc free from spywares Download Ad-Aware and
   

[JohnRolandElliott]

About port 139 : This is for the TCP NetBIOS connections, mostly with Windows machines, but also with other systems running Samba. TCP connections form "NetBIOS sessions" to support connection oriented file sharing activities. This is the third port of the original "NetBIOS trio" used by the first Windows operating system to support file sharing.

Source: grc.com

Well, at the risk of sounding like the class historian, in fact Windows supported print and file sharing long before it supported TCP/IP. Initially, running on top of DOS's real mode networking (itself an offspring of 3Com's 3+Share) I think you could use network resources from the outset. (Anyone remember Windows 1.0, which didn't even have overlapping windows ... tiled only.) This all ran on NetBEUI protocol as opposed to TCP/IP.

Also before intrinsic TCP/IP in Windows, there was NetBIOS over IPX/SPX to implement Windows file sharing in a Netware network. (Was this Windows 3.1?) Likewise, still before TCP/IP support in retail Windows, there was Windows for Workgroups, which had built-in support for peer-to-peer networking over NetBEUI and IPX/SPX.

Finally, as an add-in to WfW, there was a free download from Microsoft - "Wolverine" - to put TCP/IP support into Windows. I think Wolverine had NBT (NetBIOS-over-TCP/IP) from the git-go. Before TCP/IP, there was no Port 139. Before Wolverine, you used a third-party Winsock stack. (Anyone remember Trumpet Winsock?) If you wanted to run Microsoft Print/File Sharing over TCP/IP before Wolverine, you could install an assortment of shims and packet drivers that encapsulated TCP/IP packets into IPX/SPX packet and learn way more about NDIS and ODI than anyone should ever care to.