Rob Foehl via Postfix-users:
> There's a particularly obnoxious ESP that won't take no for an answer,
> repeatedly retrying delivery attempts despite 5xx responses -- unless
> "no" is spelled exactly "550 5.1.1 ...", apparently.
That's what Postfix says for an unknon unknown recipient:
rcpt to:<xx...@porcupine.org>
550 5.1.1 <xx...@porcupine.org>: Recipient address rejected: User unknown
> Cute. I'll just throw that into an access map, and... nope, they get
> 550 5.0.0, as noted in access(5). Makes sense, but standards compliance
> isn't a terribly compelling argument when the other side can't be
> bothered.
>
> How can I convince Postfix to stop helping and do what I said?
Are you referring to the second bullet item the section "ENHANCED
STATUS CODES"?
* When a sender address matches a REJECT action, the Postfix SMTP
server will transform a recipient DSN status (e.g., 4.1.1-4.1.6)
into the corresponding sender DSN status, and vice versa.
* When non-address information matches a REJECT action (such as
the HELO command argument or the client hostname/address), the
Postfix SMTP server will transform a sender or recipient DSN
status into a generic non-address DSN status (e.g., 4.0.0).
For good reasons Postfix tries to send replies that are 'RFC correct'.
That is, it will reply with 5.1.1 only when it detects a 'user
unknown' condition.
You can fake a 'user unknown' condition with milter-regex (a Milter
plugin) or with postfwd (a check_policy_service plugin). These can
reply with "550 5.1.1 user unknown in reply to RCPT TO", when the
remote SMTP client domain or IP address matches some pattern.
Wietse
_______________________________________________
Postfix-users mailing list -- postfix-users@postfix.org
To unsubscribe send an email to postfix-users-le...@postfix.org
