If you open a command prompt and type “ipconfig”, you’ll probably find a long list of digits such as the ones above, which would look gibberish to anyone but techies. Those numbers are, in fact, an IP address, the address of a computer on a network. This is IPv4 – it’s the fourth version created by an international standardization committee known as the Internet Engineering Task Force (IETF), and is the only one which has been adopted.
When IPv4 was created in the early 70s, few thought we would ever need more IP addresses. It was the world of mainframes and terminals; not many devices had IP addresses. But the scene quickly evolved with the 80s bringing forth personal computers, and the landscape became completely different.
Every time you connect to the internet, your ISP will assign one IP address to your company; this is a public IP address. If you want to be on the internet, you must have at least one public IP address. Think of it as your mailing address, if you will – it’s the way the rest of the internet locates you, and the way through which you find the rest of the internet.
To avoid rapidly using the entire IPv4 address space, IETF came up with the idea of private IP addresses – meaning that within your office network, IP addresses can be assigned and used in 3 ranges (192.168.x.x, 10.x.x.x and 172.16.xx through 172.31.x.x) and still kept internal; these became known as private IP addresses and they’re not found on the internet.
Since these are “private IPs”, every company can use them internally, and it doesn’t matter that they’re also being used by other companies; being internal to the company, there’s no risk of confusion. When each of these companies connects to the internet, they still use their own public IP address. Only now, they’re utilizing one public IP for the entire company rather than one per computer. This brought a great deal of public IP savings which allowed us to stretch the IPv4 lifespan for close to another 30 years. That said, each time a new internet connection is made, a new public IP is, likewise, used. DSL and cable have brought broadband into our homes so now every connected home has an IP address as well. Those factors accelerated the use of IPv4 once again. Meanwhile, cellular phones became “smart”, and wanted to be connected to the internet so they too required IP addresses. And, these days, so do cameras, DVD players, and any other “smart” device that is internet capable. So we went from a few mainframes in the early 70s, to billions and billions of devices today, all wanting to be on the internet.
At this juncture, it’s evident that IPv4 is no longer sufficient and the reasons why that is the case.
In our next post, I shall elaborate upon the various measures taken by IETF and IANA (the Internet Assigned Numbers Authority) to resolve this issue, with the introduction of IPv6.