[mail-vet-discuss] New draft for review

[John L]

> On second thought, wouldn't the MX for an address *be* a border MTA and thus 
> part of the intended recipient's administrative domain?

Yeah.  That's the place where the message hops from the senders's network 
to the recipient's network.

> An intermediate MX could do any authentication it wants, but any A-R header 
> it adds is not desirable by the receiving domain anyway.

Sorry, that's just wrong.  My wife has an address at cornell.edu which 
forwards to an address here.  Since I know the path that the mail takes 
from Cornell to here, if Cornell added a header and the message arrived 
via the known path, their header would be quite useful even though the 
message subsequently made an MX hop to get here.  Ditto for my addresses 
at acm.org, ieee.org, etc.  For SPF and other path authentication, an A-R 
from the previous MX would be greatly preferable to the alternative of 
parsing Received: headers.

Regards,
John Levine, johnl at iecc.com, Primary Perpetrator of "The Internet for Dummies",
Information Superhighwayman wanna-be, http://www.johnlevine.com, ex-Mayor
"More Wiener schnitzel, please", said Tom, revealingly.