[ietf-dkim] Discussion of Consensus check: Domain Existence Check

[Douglas Otis]

On Jun 13, 2008, at 1:17 AM, Charles Lindsey wrote:

> On Wed, 11 Jun 2008 18:06:57 +0100, Douglas Otis <dotis at mail- 
> abuse.org>
> wrote:
>
>
>> Which TLDs should be ignored?  Imposing SMTP domain requirements will
>> likely reveal a need to make many exceptions.  Do you agree there
>> should be a means for making exceptions?  Whether making address
>> assignments exclusively within MS Exchange is considered stupid (and
>> you'll find agreement there), imposing a requirement that email-
>> addresses must be valid (in some manner) changes SMTP
>> interoperability.  As it is now, recipients will normally see these
>> messages (which may not expect a response), and might even be
>> considered an alternative to the use of "do-not-reply@" local-parts.
>
> You may ignore any TLD not recognized by ICANN (for that purpose, all
> national TLDs are deemed so recognized).

The domains being ignored can _not_ be based upon it not having a  
valid TLD.  This would permit bad actors a means to employ look-alike  
spoofing.  Their spoofs might use ACE-labels for example, or things  
like ".C0M".

-Doug