single-character host names

[Mark Andrews]

In message <6.2.5.6.2.20090225140635.02c02db8 at resistor.net>, SM writes:
> At 13:46 25-02-2009, Mike Bernhardt wrote:
> >I've been looking into the RFCs regarding whether or not single-character
> >(alpha) host names are allowed or not. RFC 952 says no, but 2181 says that
> >host names must between 1 and 63 octets in length, which would appear to say
> >"yes."
>
> Section 2.1 of RFC 1123 discusses the syntax for host names and 
> clarifies RFC 952.  Host names can be up to 63 octets and the FQDNs 
> up to 255 octets (RFC 2181).  You can have a single-character host 
> name as long as it follows the syntax.

RFC 1123 does not say that.  It says:

      Host software MUST handle host names of up to 63 characters and
      SHOULD handle host names of up to 255 characters.

RFC 952 was written during the transition from a flat namespace to a
heirachical namespace.  It handled both forms of names.

	"m" as a hostname or alias is illegal.
	"m.example.net" is not illegal as a hostname or alias.

RFC 1034 does not define what is or is not legal in a host names.  It
deals with domain names which are not the same thing.

RFC 2181 does not define what is or is not legal in a host names.  It
deals with domain names which are not the same thing.

> Regards,
> -sm 
> 
> _______________________________________________
> bind-users mailing list
> bind-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/bind-users
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org