ASCII and Hex Representation of NetBIOS Names

ID: Q194203


The information in this article applies to:
  • Microsoft Windows NT Server version 4.0
  • Microsoft BackOffice Server version 4.0
  • Microsoft Windows NT Workstation version 4.0
  • Microsoft Windows 98
  • Microsoft Windows 95


SUMMARY

NetBIOS names are 16 bytes long, but they are mapped to a 32-byte wide string of alphabet (A,B...O,P) using a reversible, half-ASCII, biased encoding.


MORE INFORMATION

The algorithm used to encode NetBIOS names is as follows:

Each half-octet of the NetBIOS name is encoded into 1 byte of the 32-byte field. The first half-octet is encoded into the first byte, the second half- octet into the second byte, and so on. Each 4-bit, half-octet of the NetBIOS name is treated as an 8-bit, right-adjusted, zero-filled binary number. This number is added to the value of the ASCII character 'A' (hexadecimal 41). The resulting 8-bit number is stored in the appropriate byte.

This encoding results in a NetBIOS name being represented as a sequence of 32 ASCII, upper-case characters from the set {A,B,C...N,O,P}. The NetBIOS scope identifier is a valid domain name (without a leading dot).

An ASCII dot (2E hexadecimal) and the scope identifier are appended to the encoded form of the NetBIOS name, the result forming a valid domain name.

For example, the NetBIOS name "THE NETBIOS NAME" in the NetBIOS scope "SCOPE.ID.COM" would be represented at level one by the ASCII character string:


   FEEIEFCAEOEFFEECEJEPFDCAEOEBENEF.SCOPE.ID.COM 
The following is a list of characters and their corresponding encoded ASCII and hex values:

   Character   ASCII Code    Hex Code
   ----------------------------------

   A            EB            45 42
   B            EC            45 43
   C            ED            45 44
   D            EE            45 45
   E            EF            45 46
   F            EG            45 47
   G            EH            45 48
   H            EI            45 49
   I            EJ            45 4A
   J            EK            45 4B
   K            EL            45 4C
   L            EM            45 4D
   M            EN            45 4E
   N            EO            45 4F
   O            EP            45 50
   P            FA            46 41
   Q            FB            46 42
   R            FC            46 43
   S            FD            46 44
   T            FE            46 45
   U            FF            46 46
   V            FG            46 47
   W            FH            46 48
   X            FI            46 49
   Y            FJ            46 4A
   Z            FK            46 4B

   0            DA            44 41
   1            DB            44 42
   2            DC            44 43
   3            DD            44 44
   4            DE            44 45
   5            DF            44 46
   6            DG            44 47
   7            DH            44 48
   8            DI            44 49
   9            DJ            44 4A

   <space>      CA            43 41
   !            CB            43 42
   "            CC            43 43
   #            CD            43 44
   $            CE            43 45
   %            CF            43 46
   &            CG            43 47
   '            CH            43 48
   (            CI            43 49
   )            CJ            43 4A
   *            CK            43 4B
   +            CL            43 4C
   ,(comma)     CM            43 4D
   -(hyphen)    CN            43 4E
   .(period)    CO            43 4F
   =            DN            44 4E
   :(colon)     DK            44 4B
   ;(semicolon) DL            44 4C
   @            EA            45 41
   ^            FO            46 4F
   _(underscore)FP            46 50
   {            HL            48 4C
   }            HN            48 4E
   ~            HO            48 4F 
NOTE: The above mapping list can be useful while reading network traces because information is sent on the wire in the above encoded format.


REFERENCES

For more information, see RFC 1001.

Additional query words: kbDSupport NetBIOS Name Character Encoded Hex ASCII

Keywords :
Version : Windows:95,98;WinNT:4.0
Platform : WINDOWS winnt
Issue type : kbinfo


Last Reviewed: September 10, 1999
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