[ietf-dkim] is this a problem or not?

[Dave Crocker]

> The usual approach is by using different domains.  Disregarding the
> courtesy forwarding swamp, it makes sense for a bank to say that its
> transactional notices, e.g., "you're overdrawn", shouldn't be coming
> from any place but the bank, and shouldn't be appearing on mailing
> lists.  On the other hand, it's perfectly reasonable for employees
> to be participating in work-related mailing lists.
> 
> Since there's different policies for transactional mail and mail from
> employees and DKIM's granularity is domains, if you want to use DKIM
> and SSP, you'd best send the transaction mail from one domain and the
> personal mail from another.  I see banks doing this already.  Even the
> small ones tend to have a bunch of domains for all the variants of
> their name.


Folks,

This strikes me as pretty much a perfect explanation of the relationship 
between DKIM signing and the use of DKIM policies.

In particular, and with some wording modification, to generalize:

      When a domain wishes to apply different policies for different types
      of mail, and since DKIM's granularity is domains, you'd best sign
      and send the different types of mail using different (sub-)domains.

/d