Every packet crossing the Internet carries two addresses—where it came from and where it's going. Without these coordinates, data is lost. With them, information finds its way home across billions of devices.
IPv4 has 4.3 billion addresses. Earth has 8 billion people with multiple devices each. The math doesn't work—yet here we are. Public and private addresses, working through NAT, explain how the Internet survived its own success.
The Internet ran out of addresses in 2011. It kept working anyway—through a clever hack that was never supposed to become permanent. Here's why the real fix is still only halfway deployed.
Static IPs are for devices that need to be found. Dynamic IPs are for devices that do the finding. One is permanent identity, the other is borrowed—and the difference shapes everything about how you exist on a network.
You don't know your own public IP address—you have to ask. Here's how to find it, why you're asking a mirror, and why the answer might change tomorrow.
Your device has two addresses—one the world sees, one only your home network knows. Here's how to find the private IP your router assigns to tell your devices apart.
Every IP address on the Internet was handed out as part of a contiguous block. Here's how to read the notation that proves it.
Not every IP address belongs to the public Internet. Some ranges exist for private networks, self-communication, failure states, and group messaging—exceptions that make the whole system work.
IPv4 gave us 4.3 billion addresses. We used them all. Here's why that didn't break the Internet—and what's actually keeping it running.
IPv6 was designed in 1995. It's 2025 and we're halfway there. This isn't technical failure—it's the economics of infrastructure transitions.
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