IP Address

An IP address (Internet Protocol address) is a numerical identifier assigned to each device connected to a network using the Internet Protocol. It serves two functions: to identify the device and to indicate its location on the network, enabling data to be sent to and received from it.

IP addresses are managed by hierarchical authorities. At the highest level is IANA (Internet Assigned Numbers Authority), which allocates large blocks to five regional registries (RIRs), such as RIPE NCC for Europe and AFRINIC for Africa. The RIRs in turn allocate addresses to Internet service providers (ISPs), who distribute them to their customers.

IPv4 and IPv6

The older version, still in widespread use, is IPv4, which uses 32 bits. It is typically written as four numbers separated by periods, for example 192.0.2.1, with each number ranging from 0 to 255. The total number of IPv4 addresses is limited to approximately 4.3 billion, which led to the creation of IPv6, which uses 128 bits and is written in hexadecimal notation separated by colons.

Types and assignment

There are public addresses visible on the Internet, and private addresses that operate only within internal networks, such as those beginning with 192.168 or 10. Network Address Translation (NAT) allows multiple internal devices to share a single public address. An address can also be static (fixed) or dynamic (changing), typically assigned via the DHCP protocol.

Uses and limitations

Because an IP address is linked to a network connection, it can be used to estimate a user's general location (geolocation), to restrict access to certain services, and for security monitoring. However, an IP address identifies a connection, not a person; an address used at one time may later be assigned to a different user. VPN and proxy services mask the original address.