JSI Tip 2721. NetBIOS names are exactly 16 characters in length?


Microsoft limits a NetBIOS name to be 15 characters in lenght and uses the 16th character as the NetBIOS suffix.

All NetBIOS names are 16 characters in length. The 16th character identifies functionality installed on the registered device.

The following table lists the NetBIOS suffix in hexadecimal, otherwise it would be unprintable:

Name                Number(h)  Type  Usage
--------------------------------------------------------------------------
<computername>         00       U    Workstation Service
<computername>         01       U    Messenger Service
<\\--__MSBROWSE__>     01       G    Master Browser
<computername>         03       U    Messenger Service
<computername>         06       U    RAS Server Service
<computername>         1F       U    NetDDE Service
<computername>         20       U    File Server Service
<computername>         21       U    RAS Client Service
<computername>         22       U    Microsoft Exchange Interchange(MSMail
                                     Connector)
<computername>         23       U    Microsoft Exchange Store
<computername>         24       U    Microsoft Exchange Directory
<computername>         30       U    Modem Sharing Server Service
<computername>         31       U    Modem Sharing Client Service
<computername>         43       U    SMS Clients Remote Control
<computername>         44       U    SMS Administrators Remote Control
                                     Tool
<computername>         45       U    SMS Clients Remote Chat
<computername>         46       U    SMS Clients Remote Transfer
<computername>         4C       U    DEC Pathworks TCPIP service on
                                     Windows NT
<computername>         42       U    mccaffee anti-virus
<computername>         52       U    DEC Pathworks TCPIP service on
                                     Windows NT
<computername>         87       U    Microsoft Exchange MTA
<computername>         6A       U    Microsoft Exchange IMC
<computername>         BE       U    Network Monitor Agent
<computername>         BF       U    Network Monitor Application
<username>             03       U    Messenger Service
<domain>               00       G    Domain Name
<domain>               1B       U    Domain Master Browser
<domain>               1C       G    Domain Controllers
<domain>               1D       U    Master Browser
<domain>               1E       G    Browser Service Elections
<INet~Services>        1C       G    IIS
<IS~computer name>     00       U    IIS
<computername>         \[2B\]     U    Lotus Notes Server Service
IRISMULTICAST          \[2F\]     G    Lotus Notes
IRISNAMESERVER         \[33\]     G    Lotus Notes
Forte_$ND800ZA         \[20\]     U    DCA IrmaLan Gateway Server Service 
The NetBIOS name types describe the functionality of the registration:

Unique (U): The name may have only one IP address assigned to it. On a network device multiple occurrences of a single name may appear to be registered. The suffix may be the only unique character in the name.

Group (G): A normal group; the single name may exist with many IP addresses. WINS responds to a name query on a group name with the limited broadcast address (255.255.255.255). Because routers block the transmission of these addresses, the Internet Group was designed to service communications between subnets.

Multihomed (M): The name is unique, but due to multiple network interfaces on the same computer this configuration is necessary to permit the registration. The maximum number of addresses is 25.

Internet Group (I): This is a special configuration of the group name used to manage Windows NT Domain names.

Domain Name (D): New since Windows NT 4.0.

To use the NetBIOS suffix in an LMHOSTS entry, consider the following example:

<IP Address of Trusted PDC> <Trusted PDC Name> #PRE #DOM:<Trusted Domain Name>
<IP Address of Trusted PDC> "<Trusted Domain Name> \0x1b" #PRE

where the text within the quotes (") is exactly 20 characters. You can use the following template:

"123456789012345\0xss"

NOTE: see the following Knowledge Base articles:

Q119495 - List of Names Registered with WINS Service.

Q154608 - NETBIOS Node Status Query Returns First Instance of Uniqe Name.

Q129603 - Using Systems Management Server Remote Control over a RAS Server.


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