On Mon, Apr 07, 2025 at 01:21:44PM -0400, John Levine via mailop wrote:
> We particularly want good logging so when someone asks why didn't I
> get my update we can tell them without grepping
> through a whole day's logs.
For timely delivery status info, I'd recommend enabling VERP and having
the sending process request each of success, delay and failure
notification on delivery attempts, then just parse and feed the reports
into a database. This approach is logging infrastructure and
MTA-independent, but that said Postfix can help fill some gaps, because
it can simulate the client requesting DSN and VERP if for some reason
the actual client can't.
Postfix can also be easily configured to not defer success DSNs to a
remote system by ignoring the DSN keyword in the remote EHLO. Any
handoff to the domain's MX is then reported as a successful transfer of
responsibility to the recipient's domain, what happens after that is
their problem.
smtp_discard_ehlo_keywords = DSN,silent-discard
# For processing return traffic to VERP sender addresses
recipient_delimiter = +
# No implicit propagation of per-domain policy to sub-domains
parent_domain_matches_subdomains =
# Internal forwarded domains...
# Use of a separate "relay" transport avoids inbound delays if
# output is for some reason congested.
relay_domains = internal.example, ...
At ~100,000 messages per day performance is not a concern, this is very
modest volume.
> We also have problems of people signing up with fake addresses so I
> need to be able to collect signup confirmation failures fairly quickly
> and turn off the corresponding accounts.
These can use a separate envelope sender, and separate database tables,
and perhaps the code handlign receipt of the delivery notifications can
take immediate action as well as recording the status in a database.
Though of course some systems tempfail (4XX) invalid addresses, and
then it is less clear whether to immediately drop the account, but
perhaps for signup that's good enough???
--
Viktor.
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