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

I wonder how much more it will take before the answer to "What is my IP address?" will simply be "Look in the settings" or "Just type ip addr in the terminal".

We are so used to NAT that we don't realize how crazy it is that you essentially have to ask a stranger what's your address. It's really difficult to explain this to someone with no networking knowledge. Nothing else works this way: phone numbers, emails or postal addresses.

Phone numbers do work that way.

Phone numbers, emails, and postal addresses all still route through multiple mediaries between source and dest, and neither end ever know what path it took. In other words, they are MITMed by design. And for these mediums of communication, you want it this way for everyone's safety and sanity.

The only way this works securely with internet packets would be tor.

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.

You don’t really have to ask a stranger - you can ask your router, in a similar way you can check the door number on your street.

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.

Ask your router? Is there a generic way to do this, or do you mean "look into its vendor-specific management interface"?

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

NAT-PMP, UPnP-IGD or PCP can be used for that. Home routers usually support at least one of those, but you may have to explicitly enable it.

3 competing techs... Of course this doesn't suffice in a variety of situations which is why STUN is a thing: https://tools.ietf.org/html/rfc3489

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.

I'm NAT'd, though with an external IP, so the IP my router sees is not the same as what the world sees--while my ISP did provide me this information in an email, it's much faster for me to ask Google or whatnot than to dig the email up.

Assumes:

* You have login access to the router * Your router is directly exposed to the internet * You're not using a VPN

If your ISP is doing a CGNAT, which are becoming more and more common, not even the router knows the public address.