If you are using current LISTSERV technology, there are
a couple of different options, besides the standard
* FILTER= ALSO,userid@node
 
1) QUIET SET listname NOPOST FOR [log in to unmask]
 
or
 
2) QUIET SET listname REVIEW FOR [log in to unmask]
 
The first will outright reject postings, whereas the latter will
forward them to the OWNER (or maybe Editor?) for approval.
 
In either case, the P.C.  is notified by a message that I believe
can be found in the DEFAULT MAILTPL unless that behaviour is
overriden by a listname MAILTPL update.
 
Please review your list's FAQ/WELCOME file for netiquette
references.  Then enforce them even-handedly.
 
--  co-owner INFOSYS, TQM-L, CPARK-L, ERAPPA-L, JANITORS, LDBASE-L, et -L
URL:mailto:[log in to unmask]          "Kids: don't e-mail to strangers!"