Re: Underscores in domain names

From: Joe (joe@blarg.net)
Date: Sun Feb 11 2001 - 13:25:25 EST


On Sat, 10 Feb 2001, James MacNeil wrote:

> I got this address in a spam today:
>
> http://future_of_cars.tripod.com
>
> Are underscores allowed in host names?? It works, so I guess so.
>
> Is this always supported?

Underscores are specifically prohibited in hostnames per RFC. (Both rfc952
DNS and strict SMTP rfc821 will enforce this) The two specifically
prohibited hostname characters are the underscore ('_') and forward slash
('/').

Bind will refuse a record with an underscore with one notable exception
being CNAMEs. CNAMEs are not bound to host naming rules so you can actually
get away with it there. I wouldn't recommend trying it though.

--
Joe                                     Technical Support
General Support:  support@blarg.net     Blarg! Online Services, Inc.
Voice:  425/401-9821 or 888/66-BLARG    http://www.blarg.net



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