block everyone but contacts on my iPhone

My goodness. That's interesting. Is there some accessible list somewhere of who exactly isn't blocked? If I'm expecting a call from someone who isn't in my contact list, I'd sure like to know if it's automatically going to get through, instead of just saying, well, I THINK I once called them or their phone number was once in an e-mail. Of course, I could just put them temporarily in my contact list, but that takes a little effort.

Let me add that I have no idea who is logging all the phone calls that I make. If I called someone ten years ago, and they aren't in my contact list, are they not going to be blocked when they try to call me? Or if someone sends me a spam e-mail with phone numbers listed, are those phone numbers not going to be blocked? The latter is sort of incredible. That someone can basically unblock themselves by just sending me an e-mail with their phone number!

Ah, one extra piece of info I uncovered. That strategy blocks callers not in your contacts list *and* in your "Recent Calls" list. That latter list tops out at 100 calls. So long-ago calls are not likely to be allowed. Now, this business about fishing through your e-mails for phone numbers to allow through is vaguely invasive and, at least to my mind, not at all wise.

Thank you. Why don't they DEFINE "Unknown Callers" as people not in your contact list?

Thank you. But I guess I need to get some more detail on this. Your Apple Support link was helpful.