An IP address, short for Internet Protocol Address, is a number used to identify a device connected to a TCP/IP network like the internet.
In IP version 4 (IPv4), an address is a 32-bit number typically displayed as four decimal numbers ranging from 0 to 255, separated by periods. 18.104.22.168 is an example of a valid IP address. (IP version 6 uses 128 bits, and is typically displayed using hexadecimal notation separated by colons, with some portions being optional.)
Every device connected to a TCP/IP network is required to have a unique IP address. It’s important to realize that an IP address is assigned to a device, and that device then in turn may be capable of hosting many different and potentially unrelated services, including websites.
The internet itself is, of course, the largest TCP/IP network, and every device connected directly to it does, indeed, have a unique IP address. Confusion sometimes results from the fact that many devices are actually not connected directly to the internet, but rather through some other device, such as a router.
A router, as a device connected to the internet, is assigned an IP address on the internet, but it also establishes a completely separate network (or LAN) on which attached devices are assigned IP addresses that are unique to that local network. The router, then, handles Network Address Translation (or NAT) to give the local devices the ability to contact services on the internet, where they appear as connections from the router’s internet IP address.« Back to Glossary Index