local part of e-mail addresses (was: TOFU Design)

[Claus Assmann]

On Mon, Jul 20, 2015, Simon Josefsson wrote:
> "Neal H. Walfield" <neal at walfield.org> writes:

> > In conclusion: I think we should just use the regularized email
> > address

> I agree.  Remember that the local part is not case sensitive.

Wrong... the interpretation of the local part is subject to
the rules of the final destination.

RFC 2821             Simple Mail Transfer Protocol            April 2001
...
2.3.10 Mailbox and Address
...
   applications than simple "user names".  Consequently, and due to a
   long history of problems when intermediate hosts have attempted to
   optimize transport by modifying them, the local-part MUST be
   interpreted and assigned semantics only by the host specified in the
   domain part of the address.


See also the discussions on the DANE lists about looking up e-mail
addresses for PGP and S/MIME keys -- there's always a large
disagreement.