I do this for any inbound call, unless the caller id is someone in my contacts it can go to voicemail. If it's important they either leave a voicemail or keep trying, for repeated calls I will answer but with skepticism.
If they are in my contacts I will recognise their voice.
Not found any good proxy which works well with cisco VPN software. Charles and proxyman work intermittently at best and require disconnecting from the VPN and various such dances.
I used to send something like 250k a minute complete with delivery report processing from a single machine running a bunch of other services like 10 years ago.
If they are in my contacts I will recognise their voice.