yes, this works well. I have a similar setup at voip.ms and we have not had a telemarketer call in the more than 2 years this has been in place. In my case, I use the "caller ID filtering" feature for the white list (i.e. your contact list), and the IVR feature to ask friends and acquaintances to press 1, or others to press 2. Pressing 2 goes to voicemail. Pressing 1 rings the phone. don't forget to get the callerIDs of your local reverse911 service and add them to your contact list, if applicable in your area.