Addreturnpath, noaddreturnpath Channel Options
Adding Return-path: header fields (
When specified on a destination channel, the
addreturnpath channel option causes the MTA to add a Return-path: header field and possibly an Original-recipient: header field to all messages enqueued to the channel.
noaddreturnpath disables this feature.
The Return-path: header field will contain the current envelope from (SMTP MAIL FROM) address enclosed in angle brackets. The Original-recipient: header field will contain the value of any SMTP ORCPT parameter associated with the message's recipient(s). Original-recipient: header fields are only generated when all recipients of the current copy of the message have the same ORCPT value.
Note that the addition of Return-path: and Original-recipient: header fields is usually a function of a final delivery agent (such as a final delivery channel). Most final delivery channels know to add these header fields themselves. But for the convenience of some channels such as the
ims-ms channel, where adding a Return-path: header line in the channel program itself is not convenient, the MTA is also capable of adding the Return-Path: header itself if configured to do so via this channel option.
addreturnpath channel option is the default on the
ims-ms channel and any channel marked with one of the
lmtp* channel options;
noaddreturnpath is the default for all other channels.