Basically, back in the 1970s when the foundations for the internet were being put together, the Elders of the Internet¹ implemented something called IPv4.
IPv4 allows for around 4 billion unique numbers - or enough numbers for 4 billion devices to access the internet [If you ever look in your network settings and see numbers like 192.168 etc, etc, those are what I’m talking about].
Which was quite a lot back in the 1970s. And well within limits, given the projected growth of the internet.
Then Tim Berners-Lee came along with his “world wide web” system… And suddenly we live in a world where you can buy a digital photo frame that pulls in pictures from Facebook and Instagram. And fridges that can “dial” the ‘net to order food when they detect you’re running low.
Suddenly 4 billion unique numbers isn’t enough.
I remember writing about this back in February 2011, when the final 16M addresses were released by the main body that oversees these things, into Europe. At the time they were released to be used in addition to the existing blocks of IP addresses that were available.
As of yesterday, they’re the sole remaining ones.
It’s nothing to worry about - IPv4 has started to be replaced by IPv6.
IPv6 contains enough combinations to give six billion people a unique address. Then repeat the process across six billion different planets.
Oh, and then there’s enough numbers left to repeat the whole process - six billion people per planet, six billion planets, all with a unique IP address again.
And then again.
In other words - a world[s] that run out of IPv6 numbers? It’s beyond anything I’d venture anyone on Earth can contemplate.
Which is kinda cool.
As for the remaining IPv4 addresses? They’re now being rationed - given out in blocks of 1,000 at at time, to companies who can prove they’re working towards adapting IPv6.
¹: Any excuse to throw in a reference to The I.T. Crowd