WINS and international netbios names

Christopher R. Hertel crh at
Thu Mar 29 20:21:03 GMT 2001

> There's lots of information on the web which says "don't do that"
> as netbios names should be able to be resolved as dns names.  DNS
> names are only allowed a range of 7-bit ascii characters.

That's not true, I am afraid, for a variety of reasons.

- The only restriction placed on a NetBIOS name in the RFCs is that it 
  may not begin with an asterisk character.  The asterisk is reserved for 
  use as a wildcard lookup.  Microsoft semi-broke this when they 
  introduced the *SMBSERVER name.

- IBM's docs (the ones I could find) say only that the name may not
  contain a NUL byte ('\0'), if I recall correctly.

- Microsoft tossed out the "Best Practices" rules when they put together 
  W2K DNS.  They quote a later RFC that points out that any arbitrary 
  binary string may be included as either key or data in a DNS record and 
  used this as an excuse to require names beginning with an underscore.
  They are technically correct, but best practices are still best
  practices, IMHO.  See RFCs 883, 1034, 1035, and 2181.

In theory, *any* octet value can be encoded using RFC 1001/1002 half-ascii
encoding.  The restrictions mentioned above are either semantic (in the
case of the asterisk) or a programming limitation (in the case of the NUL
byte, which is typically used as a string terminator). 

The mapping of NetBIOS names to DNS names is also a Microsoft-ism.  The 
RFCs specified that *encoded* names might some day be placed in the DNS.

So...  Most likey what you are seeing is a character set conversion 
problem or a bug in either Microsoft's WINS or our NBNS (which are you 
testing against?).

Chris -)-----

Christopher R. Hertel -)-----                   University of Minnesota
crh at              Networking and Telecommunications Services

    Ideals are like stars; you will not succeed in touching them
    with your choose them as your guides, and following
    them you will reach your destiny.  --Carl Schultz

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