Hi, in a test i've checked if a setup with a mailbox, some mailaliases and PopCon works to deliver mails to exchange mailboxes but relalized that allthough the setup works, the exchange server sends a DSN as it tries to deliver the mail to the envelop address too which is not present on the exchange server. Upon checking against a working setup i came to the conclusion that this is due to the missing "X-Original-To" Header in the ISPConfig setup. I've checked config and saw that on a default ISPConfig installation with mail the postfix option "enable_original_recipient" is set to no. The official documentation however states that the option is set to "yes" at default. (See: https://www.postfix.org/postconf.5.html#enable_original_recipient) What is the reason that the option is set to "no" on ISPConfig system? Is it safe to change it to yes or does this break functionality?
Just found the answer in this old thread... https://forum.howtoforge.com/thread...reaks-x-original-to-header-due-to-lmtp.85580/
In server/conf there's sieve_filter.master, but you can't set a custom config for that. It states this in the first lines: Code: # This sieve script is generated by ISPConfig, any changes made will be overwritten. # You can create and activate a per-user sieve script (manually or via managesieve), # which will execute after this.
Well in the end this did not need any configuration changes on the mailserver side to fix. It was a misconception about PopCon and how the software determines what the correct recipients are. Within the softwares configuration it is possible to specify which header fields get checked to reliably determine the original recipient for this mail. In my case the mail got delivered to the correct recipient and the original mailbox(mailbox with aliases) because PopCon grabed the address from the "received for" header of the mail.
