Question PMMCLI envelope FROM aka return-path

[Toxalot]

Can anyone tell me what envelope FROM is used for email sent from PMMCLI. I looked up an old message from a failed backup to see, but that doesn't help me. The FROM and TO are the same, but then I had Administrator's profile address and the address for backup errors set to the same thing. We are now on a new server using external SMTP so the envelope FROM is critical. I thought all server-generated mail got sent from the system user @ the hostname, but that doesn't seem to be true. I don't want to miss critical error messages because it was rejected by SMTP server.

 

[mow]

The envelope-from usually gets saved in the message headers as "Return-Path:".

 

[Toxalot]

The envelope FROM aka bounce address aka MFrom that was used in the handshake and carried with the message is saved as the return-path by the receiving server. Unless the envelope FROM is specifically set in scripts, it will default to whatever is in the visible From header.

But that's not what I'm asking.

What I'm asking is where specifically does that address come from for the Plesk backup tasks. I can't tell if it uses the Administrator's profile address (or subscription owner address) or perhaps it sends to itself and sets the From to match the To. Or perhaps it gets the address from somewhere else. I need to know what to set where so that those messages will send successfully when needed. It only sends when there's an error so I don't know how I could test it.

Trying to figure out the FROM on all the assorted mail generated by the server is a bit of a nightmare. I'm trying to ensure that all these messages can get through the external SMTP server without getting rejected.