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.