“Where have all the IPs gone? Gone to users every one.”

- apologies to Pete Seeger

Have you heard? The internet is full. It’s expected to reach its limit in the next few years. This means no new users, websites, or online services. It’s like a club that’s reached capacity; they’ll have to turn people away at the door. “Here, take a pager, and we’ll call you when it’s your turn.” Is this any way to manage the internet?

Hold on a minute. It’s called the World Wide Web, right? How can this vast global resource already be full? The problem isn’t bandwidth, connections, or computer costs—it’s addresses. Like seats on an airplane, there’s a fixed number of spots on the internet. Once they’re all taken, that’s it. No more room.

This limitation is embedded in the internet’s fundamental design, specifically Internet Protocol version 4 (IPV4). When the internet was still in its infancy as a government research project used mainly by universities, a 32-bit address seemed more than enough. These 4 bytes could create over 4 billion unique addresses—4,294,96,296 to be exact. You’ll recognize them in the standard dot notation, like 127.0.0.1, the address reserved for your personal computer. Reserved addresses contribute to the shortage, but they aren’t the primary cause.

The real issue is the internet’s explosive growth, surpassing all expectations. Everyone is online or eager to get connected as soon as they can afford a computer or internet access. How many people are we talking about? Current estimates suggest 1.36 billion users, roughly 20% of the global population, and that number is rising rapidly. North America boasts a 72% usage rate, while Asia, with the largest population, sits just below 14%. With 1.36 billion users and space for 4 billion, where’s the bottleneck?

Let’s examine how addresses are distributed. The Internet Assigned Numbers Authority (IANA) and the Internet Corporation for Assigned Names and Numbers (ICANN) manage these addresses, grouping them into blocks identified by their first set of numbers, known as an octet. In our localhost example (127.0.0.1), “127” represents the first octet. Class A networks, reserved for large organizations and governments, use octets from 1 to 127. Class B networks use the 128 to 191 range, while the smallest, Class C networks, range from 192 to 223. With a limit of 126 (excluding reserved numbers), Class A networks are rare. Each Class A network can hold over 16 million hosts, while Class C networks accommodate 254 hosts. A corporation might have multiple Class C address blocks.

This block allocation, ranging from 254 to over 16 million addresses, has been part of the problem. Some organizations received far more addresses than they needed. This wasn’t a significant issue until the internet’s growth highlighted the scarcity of large, unassigned address blocks. Consequently, the rigid class system was replaced with a needs-based approach, preventing organizations from hoarding millions of unused addresses. Even this measure couldn’t permanently resolve the address shortage. We might have already depleted our addresses were it not for Network Address Translation (NAT).

NAT is built into your router. You might get a single static or dynamic IP address from your ISP, but your network could have dozens of connected devices. Your router cleverly manages requests from your network, sharing your single IP address among all users – this is NAT in action.

Despite NAT, it’s projected that we could exhaust our IP addresses by 2010, or perhaps delay the inevitable by 5 to 7 years if organizations return their unused addresses. While helpful, this is a temporary fix. The demand for IP addresses extends beyond users connecting through ISPs. Websites, email servers, IP security cameras, wireless access points, and countless other internet-connected devices all require their own global or local IP address.

The solution lies in expanding the address space with a new protocol: IPV6. This is the designated successor to IPV4 and is currently being rolled out. The U.S. government aims to transition fully to IPV6 by mid-year, and China is following suit with its Next Generation Internet. How much will IPV6 expand our capacity? It’s not double, ten times, or even a hundred times larger. The designers of IPV6 learned from past limitations. IPV6 utilizes a 128-bit address space, offering trillions upon trillions of unique addresses – more than enough for the foreseeable future.

IPV6 is the key to a fully interconnected world. Computers, phones, TVs, refrigerators, and even nanny cameras could have their own IP addresses. You could even microchip your dog and give it an online presence. Of course, new challenges emerge. NAT helps shield your network from hackers and prying eyes. With IPV6, where everything could have a globally trackable address, maintaining privacy becomes a crucial concern. However, it’s a small price to pay for an internet that remains open and accessible to all.