spf-discuss
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[spf-discuss] Relay (was: Forwarder whitelisting reloaded)

2008-01-22 07:11:35
David MacQuigg wrote:
 
At 12:11 PM 1/21/2008 -0500, Stuart wrote:
[...]
Open relays were banned over a decade ago.

Oops, I thought that RFC 5068 (BCP 134, the
former draft-hutzler-spamops) was the first
"non-informative" RFC banning open relays.

Crocker has a definition

Sure, 2821bis also uses this term.  A relay
is an MTA accepting mails from clients, and
transmitting / forwarding / relaying / sending
(pick what you like) it to another MTA.

Obviously a relay is not the begin or the end
of the whole relaying business.  And for the
reasons noted in 2821bis (and likely also in
mail-arch etc.) a relay is NOT a gateway.

A relay has certain duties like not modifying
the header, let alone the body, as specified
in 2821bis (adding trace header fields is an
exception).

IIRC Dave's term for "non-relay" is mediator,
and the place to discuss SMTP terminology is
IMO the smtp list, not this list.

Crocker does not recognize the presence of a
Border, so his "relays" can be anywhere.

That's correct, they can be anywhere.  "Relay"
is no synonym of "border MTA".  A "border MTA"
is almost always a "relay", unless it happens
to be the first or last MTA.

And maybe I'm wrong, just another reason why
trying to invent a new terminology here is no
good idea.  Just because the mail-arch terms
don't include "border", "MON", "MRN" doesn't
mean that the rest is nonsense...

BTW, the latest state of the community page
(with only one border) states that anything on
the left hand side is one "MRN".  I've no idea
if that is what Keith meant when he coined the
term.

When a "forwarder" enters the picture it is an
MRN, so far it's clear.  But to its left it's
an MON sending mail over a second border to a
second MRN.  For this case "mediator" might be
a good term, "MRN + MON combo" would be clumsy.

Or maybe not, I can't tell what Keith would do,
you can try something radical like ask him. :-)

Instead of "relay", I suggest we use the terms
Transmitter and Forwarder

I'll use these and other terms as I see fit for
the purpose of discussing an underlying concept.

Redefining "relay" wasn't on the 2821bis agenda,
"bounce" vs. "reject" was difficult enough... :-|

 Frank

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