Passive probing doesn't require a Renewal setting, but you do need to tune the Auto-delete parameter to compensate for temporary faults without overdoing the secondary probe messages. Passive probing, just like active probing, will notify you if Listserv deletes a subscriber address from the list or when one of the addresses is on the monitor list. andrew >>> [log in to unmask] 11/14/2005 11:45 AM >>> Does that mean I should use Auto-Delete= Probe(some number N) coupled with Renewal= Probe to avoid the requirement of a response? As I understand it, the Auto-Delete= passive probing only operates on subscriptions that are subject to renewal. Obviously, if the message doesn't actually detect any errors, I need to rewrite my PROBE1 template to reflect what's happening (or what I want the subscribers to understand is happening).