Next up, the practicalities of using IP addresses – which ones can be used and which ones can’t be used?
You know that there has been a huge explosion in the use of computers over the past two decades. A PC used to be a very expensive item which few people could afford; therefore, they were reserved for use by well-funded companies only. Today, nearly every house contains one or more computers.
The problem, of course, is that IPv4 was devised when only a limited number of devices were being used and there was no anticipation of this situation changing. As addresses were being allocated, it was realised that at the current rate of growth, we would quickly run out of available addresses.
Private IP Addresses
One of several solutions was to reserve some classes of addresses for anybody to use, as long as that address wasn’t used over the Internet. This range of addresses is known as private IP addresses, and this solution was created by two RFCs, 1918 and 4193. As a refresher, RFC stands for Request for Comments and is a means for engineers to submit ideas for networking methods, protocols, and technology advancements.
The ranges of private addresses are as follows:
10.x.x.x – any address starting with a 10
172.16.x.x to 172.31.x.x – any address starting with 172.16 to 172.31, inclusive
192.168.x.x – any address starting with 192.168