The internet was designed in the early 1980s with a capacity for roughly 4.3 billion IP addresses. At the time, this seemed infinite. Today, an IPv4 address is a digital commodity worth upwards of $30-$50 on the open market.
The Price of Progress
Because IPv4 is so scarce, companies like Amazon (AWS) now charge for every public IPv4 address used by your instances. This has created a multibillion-dollar secondary market where large corporations buy and sell "blocks" of IP addresses.
Why IPv6 hasn't taken over yet
- Legacy Hardware: Millions of routers and IoT devices simply don't support IPv6.
- Complex Routing: IPv6 addresses (128-bit) are harder for humans to remember and sometimes more difficult to troubleshoot.
- Economic Inertia: As long as NAT and CGNAT keep the IPv4 web running, many companies delay the cost of upgrading their entire infrastructure.
The Future of the Stack
We are currently in a "Dual Stack" era. Eventually, the cost of maintaining IPv4 will outweigh the cost of migrating, leading to an IPv6-only future for the global internet.