Configuring and using NetBIOS

Viewing NetBIOS status

The nbtstat command provides NetBIOS status. For example, it can report the status from a remote client or server. NetBIOS must have been started before its status can be obtained.

An example of the output from nbtstat is shown below.

UNIT ID =  01 00 7E 69 71 20
Local name table (13 names):

Name            Soc Num Status
^^^^^^^^^^^^^~^ x02   1 Unique Registered
TYPHOON         x20   2 Unique Registered
*SMBSERVER      x20   3 Group  Registered
TYPHOON         x00   4 Unique Registered
TREEDOM         x00   5 Group  Registered
TREEDOM         x1c   6 Group  Registered
TYPHOON~X       x00   7 Unique Registered
TREEDOM         x1e   8 Group  Registered
TYPHOON#00515   x00   9 Unique Registered
TYPHOON#00523   x00  10 Unique Registered
TREEDOM         x1d  11 Unique Registered
^^__MSBROWSE__^ x01  12 Group  Registered
TREEDOM         x1b  13 Unique Registered

Session status:
name num 65535, # sessions 1, rcv dg=0, rcv any=0
LSN	State	Local Name      Soc  Remote Name     Soc  rcvs  sends
126	ESTAB	TYPHOON         x20  ARNIE           x00     0     0

The information in the first part of the display shows the unit ID and the number of names in the ``Local name table''.

The next item, the local name table, shows the names that have been added to NetBIOS. The fields are as follows:

``Name''

Name in use.

``Soc''

Numeric value of the 16th character of the name. By convention, uppercase names are used in the SMB file sharing protocol, and lowercase names are used by other utilities. The significance of the ``Soc'' field is defined by the NetBIOS application. The SMB protocol uses this field to indicate a particular service or function. For example, a client might use the machine name in uppercase with a ``Soc'' value of 0x00 (ASCII code for the null character) to connect to a remote file-sharing server.

``Num''

Number assigned to the name by NetBIOS when the name was added to the table.

``Status''

Status of an unique name or a group name that NetBIOS has added or is adding to the name table. The following status values are possible:

``Registration pending'': NetBIOS is trying to register a name in the local name table.
``Registered'': NetBIOS has successfully registered this name in the local name table.
``Deregistered'': NetBIOS has de-registered this name from the local name table.
``Alias'': NetBIOS has detected a duplicate name in the local name table.
``Alias deregistered'': NetBIOS has detected a duplicate name with de-register pending.

The last item in the nbtstat output is the session status table. The header of this section shows the number of session table entries used, including NetBIOS LISTENs, and the number of RECEIVE DATAGRAMS and RECEIVE ANY NCBs that are posted to the NetBIOS. The session status table shows the following information:

``LSN''

NetBIOS local session number (LSN) for the session

``State''

The state of the session. Possible states are:

LISTEN: waiting for connection
CALL: attempting to connect
ESTAB: established connection
CLOSING: connection is in process of closing
CLOSED: connection is closed
ABORT: connection has been aborted

``Local Name''

local name associated with the session

``Soc''

numeric value of the 16th character of the local name

``Remote Name''

server name associated with the session

``Soc''

numeric value of the 16th character of the server name

``rcvs''

number of RECEIVE NCBs outstanding on the session

``sends''

number of SEND NCBs outstanding on the session

For more information on viewing NetBIOS status, see nbtstat(1Mtcp).