Ask HN: How do I stop spam phone calls?

I only call back people who have left a message. These days there are very, very few of those.

It's quite fun to hear the phone ring, then the tones and 'Leave a Message', followed by "beep, beep, beep, beep ..." as the autodialler disconnects at the other end.

On my mobile phone, if the call is shown as from "No Caller ID" or a plain phone number (which indicates that it is from somebody not in my contacts list), I let it go to voice-mail. Once again, no voice-mail left means no call back from me.

They don't have hundreds of numbers they are calling from. Those numbers you see are all fake. Caller-ID is trivial to fake, as it basically (before shaken/stir finally get deployed) is just passing along to your phone a value defined by the scammer.

As far as how to stop, you can't.

The best you can do is what you've done. Adjust phone settings so that only caller ID's found in your phonebook ring through. That will mean most of the fakes don't ring your phone (although they will junk up your voicemail). But should the scammer happen to randomly pick a number that is already in your phonebook, their call will ring through.

Alternatively, some people say that if you put SIT tones ( https://en.wikipedia.org/wiki/Special_information_tone ) on a voicemail greeting, that can help.