What is an IP address?

Each device that connects to the Internet needs a unique identifying number with which to communicate, called an ‘IP address’.

‘IP’ stands for ‘Internet Protocol’. There are two versions of IP that currently coexist in the global Internet: IP version 4 (IPv4) and IP version 6 (IPv6). IP addresses are made up of binary values and drive the routing of all data over the Internet. IPv4 addresses are 32 bits long, and IPv6 addresses 128 bits long.

IPv4 and IPv6 will be used for the foreseeable future; however there will be a transition from IPv4 to IPv6. Although these two protocols cannot interact with each other directly, “dual stack” systems provide facilities for exchanging data between IPv4 and IPv6.

Internet addresses are a shared public resource. Effective management and fair access to these resources is vital to the ongoing health of the Internet.

APNIC does not offer Internet addresses for sale. It registers the right to use those resources according to policies set by the community members who use them.

Internet number resources are allocated to Regional Internet Registries (RIRs) such as APNIC, by the Internet Assigned Numbers Authority (IANA), which is responsible for the global coordination of the DNS root, IP addressing, and other Internet Protocol resources.

Learn more on IP addressing.

The differences between IP addresses and domain names

Since it is difficult for people to remember long sequences of numbers, the Domain Name System (DNS) was designed to provide a distributed directory of alphabetical names that correspond to these numbers.

IP address vs Domain name
Locator vs Label
Identifies point on the Internet vs Identifies the locator
Computer-friendly vs People-friendly