...

At least as of the snapshot I'm running, 20010714, postfix does VERP just as you'd expect, merely by adding -V to the "sendmail" invocation. (It works with multiple addresses, too.) Hmmm; maybe it's time to play around with Sendmail.py again.

There seems to be no way to invoke such behavior through an SMTP connection (not surprisingly).

I lied: EHLO reports that XVERP is an optional command, and indeed MAIL FROM: <from-addr> XVERP is legal and generates a VERPed address.

Hmm. Maybe this SMTP extension is already "defined". Sure looks like one could hack SMTPDirect.py to use it.

Hmm, hmm, hmm.

At least Courier and Postfix seem to implement this extension.

http://courier.sourceforge.net/intro.html http://www.postfix.org

continuing 'hmm'-ing.