How to respect anonymous incoming CallerID and not send it to endpoints?


When someone is calling one of my DIDs and has requested to be anonymous, my provider is sending me the call mentioning the anonymity request via using the P-Asserted-Identity but also sends the actual number.

The problem is that the actual number gets passed on to whatever destination extension I have set. How can I prevent the calls that are meant to be anonymous from passing the number to the destination extensions? Ideally the extensions should see something like “anonymous” instead of the number.
I tried everything however I could not make it work. I am confused…

An example below is when I am calling from another (external line) and I am using anonymous:

From sip (myHIDDEN-TelephoneNumber).at.x.x.x.x
P-Asserted-Identity sip
Privacy id

Many thanks for any help!

Hasn’t anyone experienced the same problem?
Or maybe I am doing something wrong?