on 6/7/2003 3:57 PM Spencer Dawkins wrote:
Why wouldn't we have mail sending applications that spoke (I'm
making this up) SMTP and MT2, with different URL schemes
(mailto: for SMTP, mailtoauth: for MT2) associated with our
correspondents, let correspondents advertise both ways of being
reached on Vcards, etc., and not worry about gateways?
Let's separate those concepts.
First, regarding the need for gateways, people will use them no matter
what we say, since there will always be people with mixed installations,
people who need mail from both networks (eg, sales and support), and so
forth. If we dont specify the gateway behavior, the only predictable
outcome is that people will build them without guidance. If we specify
that they cannot be made, people will still make them, and without
guidance. Clearly, the only workable strategy is to specify them, and to
do so in such a way that folks like Paul can reject mail that ever
travelled across a legacy network (that's going to be tough in toto,
considering that MUAs will probably be built to use SMTP as the first-hop
service for a very long time to come).
As for the use of an alternate URI, those are used to tell the viewer
which protocol to use. In the case of outbound mail, it would effectively
be a way for the message recipient to tell the message sender that they
have to use MT2 for the first-hop of the message, which doesn't make a lot
of sense outside closed environments. Furthermore, what happened to the
message after the first-hop would be a result of the mail-routing
information in between the first and last hops, and would not necessarily
be determined by the protocol that the sender used for the first-hop. So,
URIs can't really be used to control the delivery path.
--
Eric A. Hall http://www.ehsco.com/
Internet Core Protocols http://www.oreilly.com/catalog/coreprot/