An IP address, short for Internet Protocol address, is a unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It serves two primary functions: identifying the host or network interface and providing the location addressing of that device in a network.

There are two main versions of IP addresses in use today:

• IPv4 (Internet Protocol version 4): IPv4 addresses consist of a series of four sets of numbers, each ranging from 0 to 255, separated by periods. For example, 192.168.0.1 is a common IPv4 address format. IPv4 addresses have a limited supply and are in high demand due to the growth of the internet.
• IPv6 (Internet Protocol version 6): IPv6 addresses were introduced to address the exhaustion of IPv4 addresses. IPv6 addresses are significantly longer and use hexadecimal notation, separated by colons. For example, 2001:0db8:85a3:0000:0000:8a2e:0370:7334 is an example of an IPv6 address.

Addresses can be:

• Local.
• Global.

RIRs

RIRs are organizations that are responsible for the allocation and registration of IP addresses. They primarily allocate IP addresses to ISPs and larger organizations.

Here they are:

• American Registry for Internet Numbers (ARIN) in North America.
• RIPE Network Coordination Centre (RIPE NCC) in Europe, Middle East, and Central Asia.
• Asia-Pacific Network Information Centre (APNIC) in the Asia-Pacific region.

Marketplaces

• Prefix Broker.
• IPv4.Global.
• IP Trading.

Leasing services:

• Heficed.
• IPXO.