On Mon, Jun 13, 2005 at 04:13:10PM -0400, John R Levine wrote:
* MDAs SHALL NOT accept mail to recipients for which that MDA has
no arrangement to perform delivery.
then it should apply not only to the MDA, but more generally to (inbound)
gateways and backup MX hosts. In other words, the definition of an MDA
needs to be extended to include all MX hosts for the recipient's domain,
rather than just the systems performing the actual mailbox delivery.
That's overreaching, unfortunately. I would agree with a SHOULD NOT for
MTAs, but there are often sensible reasons that an MTA doesn't have access
to the database of valid downstream mailboxes. As an edge case, but not a
totally arcane one, there are situations where the delivery is handled by
a program and until you run the program you can't tell whether the message
will work or not.
So perhaps a MUST/SHALL not for the MDA and a should not for the MX
MTA, but this hinges of the meaning of "recipients for which that M?A
has no arrangement to perform delivery"... The "arrangement" could be
interpreted to support suitable wildcards when necessary. Perhaps this
comment needs more clarification.
--
Viktor.
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