On Thu, 2004-04-22 at 17:51, Ted Hardie wrote:
<snip>
So my question one: is it valuable for a domain to be able to list the set
of hosts it "employs" as outbound MTAs?
Until common practice allow reliance on some domain assertion, any SMTP
originating domain field claiming the IP connection establishes a
"responsible" domain. Prior to that point in time, a notice of a no
responsible domain discovered could be added, displayed by the MUA, and
used to sort the mail. To make this more useful, after enough time to
allow adoption of recommended practices, if no domain field claims the
connecting IP or the mail carries this notice, then no bounce is
produced and the mail is silently dropped.
My question two: is it valuable for a domain to be able to list the set of
hosts it is "responsible for" as outbound MTAs?
This seems to raise the question as to how headers are handled to allow
forwarding. Each SMTP server is responsible for asserting a domain by
some recommended means via SMTP fields and claiming its IP via DNS
through the asserted domain. As a practical matter, the IPs claimed by
the asserted domain should not extend to all possible SMTP server IPs
used to forward mail.
-Doug