Bill Cole:
> I recently updated a Postfix system from 2.4 to 2.9 and I have found
> what I believe is a change in behavior for reject_unknown_sender_domain
> which is confusing. In the past, an effective means of dealing with some
Sort answer: Postfix does not pass SERVFAIL, it just rejects them later.
Long answer: Postfix 2.6 and later reject the unknown sender
- With $unknown_address_tempfail_action after temporary lookup error
(including timeout and SERVFAIL). Earlier Postfix versions
hard-coded the result.
- With $unknown_address_reject_code after all other lookup errors.
Wietse
unknown_address_tempfail_action (default: $reject_tempfail_action)
The Postfix SMTP server's action when reject_unknown_sender_domain or
reject_unknown_recipient_domain fail due to a temporary error condi-
tion. Specify "defer" to defer the remote SMTP client request immedi-
ately. With the default "defer_if_permit" action, the Postfix SMTP
server continues to look for opportunities to reject mail, and defers
the client request only if it would otherwise be accepted.
This feature is available in Postfix 2.6 and later.
