Hi,

I run sendmail locally, only as the local MDA (mail delivery agent),
just because I use fetchmail which requires that sendmail be running
locally as the local MDA.

Now, I've configured my mailer so that it connects to my ISP's SMTP
hub for the outgoing mail, which takes care of Return-Path: among
other things.

Having individual dial-up hosts do DNS look-ups and SMTP is quite
inefficient, so it is better to forward all out-going messages to your
ISP's SMTP hub (or so I'm told).

I used to do just that (spool out-going messages and later forward
them to the SMTP hub) with locally running sendmail last year, but I
can't seem to find the variable for this purpose in my
/etc/sendmail.cf anymore.  CF, a tool for generating sendmail.cf from
more human-friendly spec, might help.

I haven't used CF but it might help with rewriting Return-Path:,
maybe.

Ken