Subject: RE: [ietf-dkim] Underscore considerations

From: "Hallam-Baker, Phillip" <[email-masked]>
Date: Fri, 9 Jun 2006 12:33:00 -0700

> [mailto:[email-masked]] On Behalf Of Paul Hoffman

> >Domain names are limited to alphabetic characters, digits and hyphen.
> 
> No, *host names* are restricted to alphabetic characters, 
> digits and hyphen. This has been discussed, ad nauseum, for decades.

Absolutely right, and there is plenty of software already out there that enforces the restriction.

It is not possible to reliably send email to a domain name with an underscore or to connect to a Web site. 

The security requirements here were all considered at exhaustive length in the DNSEXT working group close to a decade ago.

End of discussion.

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From: Douglas Otis <[email-masked]>
Date: Fri, 9 Jun 2006 15:23:26 -0700

> that enforces the restriction.

DKIM specifically does _not_ enforce this restriction.  These labels  
can and do exist, but not normally as registered names.

> underscore or to connect to a Web site.

No one has suggested the use of '_domainkey" is to locate a server.

> The security requirements here were all considered at exhaustive  
> length in the DNSEXT working group close to a decade ago.

This issue is not about DNS security.   This issue is about the use  
of a _domainkey subdomain within a higher level domain and is  
unrelated to prior DNS related concerns.

-Doug