For the particular list of interest, locate the template MSG_POSTING_REJECT_NOTAUTH and insert these three lines at the top:
.TY &DATE &TIME &LISTNAME; auth-drop &FROMID; &MSGREF;
.* cancel the notification, reduce spam back-scatter
.QQ
The .TY line causes a log entry so the site admin will have some info about what happened if questions arise later about why a certain message did not go through. The second line is commentary, explaining (mostly for my own benefit) why I did this to my template. The .QQ instructs LISTSERV to cancel the message it is currently using this template to prepare - and that is the precise answer to your question. Note that in your template the dot on each line must appear in the first column.
>>> Marc Frei <[log in to unmask]> 12/10/07 6:22 AM >>>
Dear site administrators,
is there a way to reject/discard postings received from non-subscribers *without* sending a note to the poster stating that they are not allowed to post?
Thank you very much in advance and kind regards,
Marc Frei