Why is "TCP/IP Netbios Helper" service required for non netbios connection


  • Hello,

    I am facing a weird problem here.

    I am building a sub-network for a department and, for many good reasons, I don't want netbios to be used on that sub-network.

    So I've disabled NetBios in the connection properties of the 2 test computers that are part, for the moment, of my sub-network.  I've also turned off the "TCP/IP Netbios Helper" : I understand (from its name) that this service is needed only if netbios is used over TCP/IP, which is not my case.

    Now, even by using the IP of the machines, I am not able to create connect to a share (using net use).  In order to connect to a share, the machine needs to have the "TCP/IP Netbios Helper" working.

    And surprisingly, I am able to connect to a share using machine name even if the netbios over tcp/ip is disdabled.

    Can somebody point me to in-depth documentation on how to work with shares by having both netbios disabled and "TCP/IP Netbios Helper" turned off.


    Tuesday, May 11, 2010 4:13 PM

All replies

  •    Microsoft has traditionally used Netbios names for file and printer sharing. Originally it used Netbeui but this was modified to Netbios over TCP/IP as TCP/IP became so popular.

      If you disable Netbios over TCP/IP you have to depend entirely on DNS for name resolution and file sharing. If any of you applications rely on Netbios names, they will fail.


    Tuesday, May 11, 2010 11:48 PM
  • OK but files and printer sharings can work without NetBios, by being referenced by IP or FQDN, right?
    Wednesday, May 12, 2010 12:32 PM
  •   Indeed, but I would not expect that to require the TCP/IP Netbios helper service. That uses SMB over TCP and uses port 445, not the Netbios ports.




    Thursday, May 13, 2010 2:19 AM
  • TCP/IP Netbios Helper service helps make things work when you don't use Netbios on your network and you use SMB (file sharing, etc) connections to servers over IPv4.

    It plays a part in the ability to connect to servers using \\server.corp.contoso.com or \\ipaddress.  Several Active Directory functions will not work when that service is disabled and you have Netbios off in your network.

    If you have Netbios off in the network card settings, Netbios data will not be sent from a computer, so you don't need to worry about that service being started. 

    Tuesday, May 18, 2010 8:03 PM
  •   Thanks, Tod.


    Wednesday, May 19, 2010 1:42 AM
  • Well, 3 things here.

    First, on a simple logic base, it is amazing that a service called "TCP/IP Netbios helper service" is required in "the ability to connect to servers using server.corp.contoso.com".  We all agree that a DNS resolution should not required a netbios "helper".

    Second, I don't really belong to the shool that doesnt care leaving default-installed services opened, if they are not required.  In my experience, a proper Windows installation is when only needed services/ports are opened, for memory, stability and security reason.

    Third, like many network administrators, I put many efforts trying to control broadcast on my network, and NetBios is a broadcaster champion.  Now if I leave the "TCP/IP Netbios helper service" opened, I get stucked with netBios broadcast I want to get rid of, even when I disable the network card netbios feature.

    So to make it short, there is no real advantage disabling the NIC netbios feature in a windows network using shared devices : it does not stop the broadcast and because you cannot really stop "TCP/IP Netbios helper service", your are still able to access windows shared device !

    Wednesday, May 19, 2010 7:34 PM
  •   I think that you should re-read what Tod said. He did not say that you are stuck with Netbios if you have the Netbios helper service running. He said that the service helps use SMB over IPv4 when you do not have Netbios enabled. It is Netbios helper is so far as it enables you to use Netbios-type SMB file sharing even if Netbios over TCP/IP is not active.

       Would you be happier if it was called the "TCP/IP SMB helper service"? Netbios and SMB are so closely linked that the two terms have become pretty much interchangable.


    Thursday, May 20, 2010 2:37 AM