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Re: Strict RFC x821 Compliant: HELO/EHLO

2005-07-03 11:16:53

On Sun July 3 2005 11:43, Tony Finch wrote:

On Sat, 2 Jul 2005, Claus Assmann wrote:

How do you know it's not a domain? Do you perform a DNS lookup?

See the discussion in RFC 1123 section 2.1: "a valid host name can never
have the dotted-decimal form #.#.#.#, since at least the highest-level
component label will be alphabetic."

True, at least to the present...  See RFC 3696 (where the top-level
is not numeric 1123 reference is also mentioned); if ICANN goes
crazy, that rule might not apply in the future.