What an IP address actually is

Addressing

Every device on a network needs a way to be found. An IP address is that identifier.

IPv4

Four numbers, each 0-255, written with dots: 192.168.1.14. That is 32 bits, which allows about 4.3 billion addresses — far fewer than there are devices, which is why private ranges and NAT exist.

Private ranges

Three blocks are reserved for private networks and are never routed on the public internet:

• 10.0.0.0/8
• 172.16.0.0/12
• 192.168.0.0/16

Your router hands you one of these, then translates between it and its single public address on the way out.