On Sat, Sep 01, 2018 at 03:27:59PM +0200, J. Fahrner wrote:
> Hi,
> my spam blocking rules don't allow a reply-to address to freemail addresses.
> Today I received a message from this list with a gmail.com replyto address
> (which was rejected).
> I'm wondering why this list allows replyto addresses which contain other
> addresses than this list. That makes no sense to me. Replies to list
> messages should always go to the list.

The reply-to header is to indicate where to send a message to the
original author. The author might, for example, be temporarilly
away from his usual site and still want to indicate where he
normally receives email. This might be useful, for example, to
make a private, off-list reply.

The 'list-post' header is to indicate how to reply to the list.

Proper email programs distinguish between these and recognise both.
Proper mailing-list software don't get in the way.

-- hendrik