Underscores in host names

Tony Finch dot at dotat.at
Thu May 19 15:25:56 UTC 2005


On Thu, 19 May 2005, Roger Marquis wrote:
>
> As it should.  I wish it would also return a null for hostnames
> containing sequential non-alphanumerics (--, ---, __, ___, ...).

It is possible to reject multiple dots, both in theory and in practice (in
fact it's a useful for spotting certain kinds of spamware that generates
bogus HELO domains).

You can't reject double hyphens because they are permitted by the syntax
and used by IDN, for example.

Tony.
-- 
f.a.n.finch  <dot at dotat.at>  http://dotat.at/
BISCAY: WEST 5 OR 6 BECOMING VARIABLE 3 OR 4. SHOWERS AT FIRST. MODERATE OR
GOOD.



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