On 9/13/2006 16:35, A.Omer Koker wrote: > > Or you might use a service that asks for the sender to confirm their email > authenticity by clicking on a link and adding them to your whitelist. > Since the message specifically asks the user to click a link (http) there is > no valid (or another /dev/null) return email adr catching any loops or error > messages. I ran across this service some time ago but misplaced the link > so if someone else knows what im talking about PLEASE send links on > company/applications that does this. > Challenge/response is just another form of back-scatter which will get you blacklisted by some sites. -- Paul Russell, Senior Systems Administrator OIT Messaging Services Team University of Notre Dame [log in to unmask]