said by Arne Bolen: said by JoeSchmoe007:
I am finding blacklist less and less effective. More often than not it is new number. I am thinking of white-listing known contacts, everyone else has to dial one digit to be connected, another - to leave a message. The only concern is how many legitimate calls I will lose if I decide to do that.
Start by adding all your legit phone contacts to the Contacts. Remember to set Contact Type to Business, Friend or Family. Do this for every caller, even if you don't except to receive more calls from the caller.
Next step is to use both White Listing and Black Listing. This is my Call Flow taking care of robocalls, telemarketer calls and other unwanted calls.
Calls from numbers marked as Business, Friend or Family will go to my SIP device (or my cellphone).
Calls from other numbers will go to a simple IVR asking the caller to press 1 to ring my phone or press 2 to leave a voicemail. If you want it more personal you can upload a recording.
Anonymous calls are routed to an extension with an IVR which just say that anonymous calls are not accepted.
You just need to add a contact with the phone number zero. It doesn't matter what you set the country to, that one single contact record takes care of all anonymous calls.
It's very unlikely you will lose legitimate calls with this Call Flow. If you route anonymous calls (SPAM) to the Press Key Control there is no risk of losing legitimate calls.
I created a workflow similar to this.
I wish I could edit my original post to reflect this.