As others have mentioned, there is a CONTENT_FILTER template available (depending on how recent the version is of your site software). How it is used is open to some personal interpretation. Here's one I have in place: Subject: Out of office Action: MODERATE OOO messages are not allowed on this list. Subject: out of office Action: MODERATE OOO messages are not allowed on this list. Subject: Out of the office Action: MODERATE OOO messages are not allowed on this list. Text: Out of office Action: MODERATE OOO messages are not allowed on this list. Text: Out of the office Action: MODERATE OOO messages are not allowed on this list. Text: out of the office Action: MODERATE OOO messages are not allowed on this list. Text: OutoftheOffice Action: MODERATE OOO messages are not allowed on this list. Subject: OutoftheOffice Action: MODERATE OOO messages are not allowed on this list. Text: out of my office Action: MODERATE OOO messages are not allowed on this list. Text: away from my office Action: MODERATE OOO messages are not allowed on this list. Subject:: Action: REJECT Please resubmit your message with a non-blank subject. Note that in the case of the "MODERATE" action choice, the following text "OOO messages are not allowed on this list." is merely documentary within the template, LISTSERV does nothing with it. I have had one case where someone wrote within the body of their message one of the phrases above (in context of advising the list of some vacation plans coming up), and wanted to know why their mail to the list was coming back to them for approval (it was the list owner) instead of just going out - and forwarded to me the approval request. I recognized the trigger phrase and explained to them what was going on. This illustrates my logic for using Moderate instead of Reject here, but that depends on the list involved, and how much bother the owner/moderator is willing to tolerate with actual vacation rule messages coming in. I'm also concerned that rejecting auto-reply messages might trigger a mail loop, if the other side auto-replies to the rejection notice. >>> [log in to unmask] 4/12/2007 3:30:10 PM >>> I have a request from a list owner to block vacation reply messages to the list. I told her that I have no control over auto-reply systems in other places, but I might be able to do something about our own. Can I? What I'm thinking would work would be to set up a regular expression filter, probably on the subject line but if an arbitrary header line could be used that would be better. Alternately, is there a specific header line that Listserv uses to recognize auto-replies that we could insert into our system? Any help appreciated. Thanks, - Mark -- Mark Berman, Director for Networks & Systems Williams College, OIT, Jesup Hall Williamstown, MA. 01267 413-597-2092