What we were trying to accomplish was the auto-deletion of bad addresses and general error handling without a lot of time-consuming human bounce administration. However, recently it seems aol.com, yahoo.com, hotmail.com, themail.com, and others have started rejecting bounces outright, causing large numbers of good subscriber addresses to be deleted from our lists. We then tried to disable probing all-together and simply handle the bounces ourselves, however this is not possible due to the fact that we use Mail-Merge for our distributions, (see post from Ben Parker). Now we are simply trying to find a method of dealing with probes so that good subscribers are not deleted or told that their email accounts are not receiving mail, when they obviously are, and we are not overwhelmed with the administrative tasks including fielding probe failures. I am simply trying to find a happy medium where our subscriber list is protected and we don’t receive 1000+ error messages a day. I agree whole-heartedly with your statement: Any procedure that you successfully implement today may not satisfy tomorrow -- "it" tends to be a moving target. Probing worked great for us until last month, when, suddenly, the rules seemed to change. Now we can’t trust it and I’m not sure what to do next. I have studied the documentation thoroughly, however I still don’t quite understand how probing works and the subtle art of probe tuning to find our happy medium.