"-" and "_" in domain name

Jerry Kemp bind at twlight.net
Fri Feb 14 14:38:18 UTC 2003


It is my understanding that rfc952 is still valid and that underscores 
("_") are illegal characters for host names.  Its been a while since I 
have worked with any of the legacy ms stuff but I don't believe that ms 
is stuffing underscores ("_") in hostnames, it is my understanding that 
they are using them in domain names, which is ok.

Can someone correct me if this is incorrect.

Thanks,

Jerry K





On Friday, February 14, 2003, at 07:18  AM, Joseph S D Yao wrote:

> Bottom line:
>
> DNS, per all the RFCs, allows any character.
>
> BIND used to disallow some characters, but now allows all characters,
> IIRC.
>
> The "-" character is always acceptable in host names and other domain
> names.
>
> The "_" character may not be used in host names, and I believe is
> therefore deprecated - at least by some - in "real" domain names.
> Microsoft, of course, decided to use them in some of its proprietary
> stuff.  I guess that's redundant.



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