On Sat, Aug 07, 2021 at 09:22:04AM -0700, Ned Freed wrote:
A single token describes all of the recipients? Or do you simply generate more
than one Delivered-to: in the same message?
No. Only one "Delivered-To:" per delivery of a given message to a
target recipient.
Let's make this concrete. We have these aliases:
alias1: local-recipient-1, local-recipient-2
alias2: remote-recipient-1, remote-recipient-2
In Postfix, when a message is sent to "alias1", the copy delivered to
"local-recipient-1" will have (with @domain suffixes as appropriate).
Delivered-To: local-recipient-1
and the copy delivered to "local-recipient-2" will have:
Delivered-To: local-recipient-2
When a message is sent to "alias2", there will be single
Delivered-To: alias2
prepended to a single message with two remote envelope recipients,
namely: remote-recipient-1 and remote-recipient-2.
How many message copies do these generate, and what fields are added?
Remote deliveries are combined and get "Delivered-To" set to the input
alias, local deliveries are one at a time, and get a "Delivered-To" of
underlying mailbox address for that recipient.
But that said, this only applies to alias expansion in local delivery,
Postfix also supports (virtual) aliasing of recipients when relaying,
and there are no "Delivered-To:" headers added when relaying also
involves envelope recipient rewriting. Thus a border MTA relaying
to an internal mailhub via SMTP and doing (e.g. LDAP based) rewriting
from the public domain to an internal domain does not treat such
rewriting as "delivery", it is merely rewrite-based relaying.
And while we're at it, what does
alias3: alias3, extra-recipient-1
do?
One copy is delivered to the user "alias3" (presumed to exist), and
another to "extra-recipient-1". Both copies have the same
"Delivered-To" of "alias3".
--
Viktor.
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