An IP address is essential for the internet to work, but what is it exactly? And what are the differences between IPv4 and IPv6? We’ll explain.
IP Addresses in General
Every computer that is connected to the internet or any other (internal) network has a number that makes it visible to all other computers on that particular network. You can compare this with telephone numbers. To make it possible for computers to find and identify each other, they need their own number. These numbers are the IP addresses. An IP address on the internet is usually linked to a company or agency. This way you can find out where operations that were done under a certain IP address come from. For people who work from home, the IP address identifies their internet provider.
IPv4 uses addresses of 32 bits (4 bytes). With this amount of bits a maximum of 4,294,967,296 addresses are possible. Many address ranges are reserved for local networks and multicast addresses, among others. As a result, the maximum number of IP addresses is not fully usable.
To address the scarcity of address space within IPv4, among other things, network address translation (NAT), also known as IP masquerading, has been developed. This allows the hosts of an intranet with IP addresses from the private address space to be addressed. The NAT router presents this to the outside as a single IP address so only one IP address needs actually routed and assigned, while hundreds of hosts can use it.
A major disadvantage of NAT is that only outgoing connections are possible as standard. Enabling incoming connections requires specific solutions that doesn’t always work well. Mostly due to the limited number of addresses of IPv4, this protocol is followed by IPv6.
A structural solution for the scarcity of address space in IPv4 can be found in its successor: IPv6. In IPv6, there are 128 bits available for an IP address, and the theoretical upper limit is therefore 340,282,366,920,938,463,463,374,607,431,768,211,456 IP addresses. Just as with IPv4, in practice, addresses are used again as network address and broadcast address, but the number of IP addresses that can be assigned is huge: trillions of addresses per person.
Although the subsequent IPv4 protocol sounds good, there is still too little demand for it worldwide. Why this is and why it is important that your website can be reached via IPv6 is explained in another blog article.