[ietf-dkim] Are subdomains like parent domains?

[John Levine]

>> What I was asking a few messages back is why anyone who's actually
>> involved in running e-mail would care whether someone forged
>> beans.rice.a.foo.com.
>
> Yahoo and Hotmail seem to be good candidates to want this. I'm open to
> hearing otherwise from them. I think a lack of response on this list
> is not equivalent to a negative response, though.

But you're assuming your conclusions again.  I've never heard anyone from 
Yahoo claim that they want automatic ADSP coverage for 
random.junk.yahoo.com, so I see no reason to think that they do.  I've 
never heard anyone from Hotmail express any interest in ADSP at all.

People don't treat mail from fred at foo.hotmail.com as being the same as 
fred at hotmail.com.  Yahoo has a small number of well known subdomains they 
use for mail, e.g., groups.yahoo.com, but again, fred at foo.yahoo.com isn't 
the same as fred at yahoo.com either.

Can you show some real life examples where mail from subdomains is treated 
as being mail from the parent domain?  This is a real question -- I can't 
think of any other than some minor elderly special cases but I'm willing 
to believe I'm overlooking something.


Also, keep in mind that if despite the fact that it doesn't matter, you 
really really REALLY want full ADSP coverage on every possible subdomain, 
you can always hire someone to write a specialized DNS server to provide 
it for you, which I think would cover Yahoo and Microsoft.  The question 
is what needs to happen in the general case.

R's,
John