One possible option is to locate the template
"MSG_POSTING_CONFIRM_SENDER" for the affected list(s), and insert three
lines, like this:

 .bb &NON_MEMBER = 1
 To cut down on spam,

 .TY &DATE &TIME &LISTNAME; spam-drop &FROMID; &MSGREF;
 .* cancel the confirm request, reduce spam back-scatter
 .QQ

 .else
 For security reasons,

You should recognize how things fit plainly enough once you access the
original version of the template.  Note that in your template leading
spaces are not allowed, the dot/period must appear in the first column
of each line, I have indented here for visual clarity. Once you apply
this change, any message arriving for the list from a non-subscriber
address will be ignored.

You might not want the .TY line in your situation, I have it so there
is at least some trail of what has gone on - in the event of some
complaint eventuality, I can go through the logfile to identify the
stuff that got discarded by this technique.

To the specific item in your request about domain selection, you may be
able to cook up something to parse the FROMID variable and make a
determination from that, but I have not tried it.

No lifeguard on duty, swim at your own risk.


>>> [log in to unmask] 12/4/2006 4:11:49 PM >>>
How can we prevent Listserv from bouncing error messages to domains
other than our own? We have a situation where internet "users" that are
not list members are sending post messages to our lists and listserv is
sending error messages back to what appears to be
non-existant/bogus/spoofed Reply-To email addresses. What I am looking
for is something similar to preventing Out-of-Office replys to the
internet.