Ifconfig.co – Hacker-friendly “What is my IP address”

Phone numbers do work that way.

Are you referring to country code prefixes?

Their point is that you can always give your number to anyone and they can directly use it to contact you. It's never unclear what number to give someone so they can reach you. Yeah calls have to be routed, but routes are implicit, not something you have to worry about as src or dest.

No, your own phone number.

Say you're at home, you have a landline, and you don't know what your own phone number is. How do you get it? You call someone with caller ID, and ask them to tell you what number you called from.

There are numbers one can call for ANI / ANAC info from a landline. They vary by carrier and sometimes region. MCI has a well-known line that reads back your number.

Of course, I haven't had a land line in years and my cell phones tell me their numbers in the settings.

Yeah that's exactly asking a stranger to tell you your address

I'm referring to the fact that people don't know their own phone numbers, and instead of reading it, they'll call you and the receiver sees the number.

They don't always. Sometimes you have to use one of those pound sign codes, but even that sometimes comes up empty.

So like I said, you call someone to get your number. Like how you google what your ip address is.