Hi
Are others also experiencing issues when temp failing arbitrary recipients from mailout01.mail.admin.ch ?
To explain the situation:
Our spamfilter gives the recipient to choice to either reject, quarantine aka spamfolder or accept an email classified as spam.
Example:
Alice sends spam to Bob and Charlie
Bob wants spam rejected Charlie wants spam quarantined.
Spam can only be rejected after the DATA phase, when both recipients have been accepted during RCPT TO.
Dropping Bob from the recipient list and only delivering to Charlie is a NO GO, we confirmed the RCPT TO to Bob with 250 so we have to deliver.
Rejecting the whole email does contradict the setting of Charlie.
To solve this, we tempfail any recipients whose spam settings differ from the first recipient like this:
MAIL FROM:alice@example.com 250 2.1.0 Ok RCPT TO:bob@example.net 250 2.1.5 Ok RCPT TO:charlie@example.net 452 4.5.3 Resend separately
452 4.5.3 is the same code used to indicate 'too many recipients' and therefore triggers an immediate fork of the original message to the remaining recipients on the sending MTA usually without any notable delay.
The only server which seems to regularly stop transmitting the email to the remaining recipients and returns a 'hard bounce' to the sender after having sent the email to 'some' of the recipients is mailout01.mail.admin.ch
Anyone observing the same issue? Anyone having a contact at BIT which could help with further investigation into the cause of the issue observed? I attempted to open a case some time ago but got no where.