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Re: Bounce/System Notification Address Verification

2005-06-30 05:14:28

On Thu June 30 2005 01:46, Robert A. Rosenberg wrote:

At 08:02 -0400 on 06/29/2005, Bruce Lilly wrote about Re: 
Bounce/System Notification Address Verification:

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To: admin-group(_at_)example(_dot_)net
...

which may well be expanded to multiple RCPT TO mailboxes.

... at the receiving end AFTER reception. It comes in as ONE address 
and when delivery is attempted, the message is cloned for delivery to 
multiple addresses/mailboxes.

Not necessarily; for better or worse, a number of sites use multiple
MTA relays within their own administrative domain, and aliasing
expansion might well occur at a separate upstream host from the one
effecting actual delivery.  There is nothing particulary
non-compliant about such a configuration, though it does have the
characteristic of forcing a bounce where a single-host arrangement
might be able to return an SMTO 5xx reply code -- of course that's
the case for any multi-hop store-and-forward SMTP path; a reply
code w/o bounce generally only occurs when the sender directly
connects to the recipient's host as shown in RFC 821 Figure 1,
repeated in RFC 2822, with no intermediate relay(s) or gateway(s).


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