A software interface
computers, enabled by default, that allows the use of legacy NetBIOS
-based services via a TCP/IP
network. Such resources include file sharing on Windows 95
, Windows 98
and possibly Windows ME
systems. I think Samba
also still uses NetBT for its services. It must be enabled if you want to provide or access
legacy resources. The name is often abbreviated to NetBT
Enabling this option opens the following TCP/IP ports on the network interface:
The upshot of all this is: Disable NetBT. Modern Windows systems (2000/XP and later) use CIFS to provide File/Print/Named pipe Sharing natively through TCP/IP. Failing to do so can leave your computer vulnerable, especially if you connect to the Internet and your ISP isn't intelligent enough to block the ports themselves.
If you need to access/provide services to legacy Windows 9x systems then consider installing the NetBEUI transport protocol on the systems involved. NetBEUI is the transport that NetBT is supposed to replace; since it is a non-routable protocol it cannot be accessed "accidently" by people outside your LAN.
I am told that Windows can also use IPX as a transport for NetBIOS; you may find this convenient if you already have IPX installed (or don't want to install NetBEUI).
The only reason you should enable NetBT is if you need to access/provide legacy services to machines accross a TCP/IP network such as the Internet and there are no secure alternative protocols or tunneling systems available, such as Terminal Services and SFTP, or VPN and SSH.