Why this matters
When a computer "has internet but cannot see the printer", or two devices keep knocking each other off the network, the cause is often an addressing problem. IT support adverts in Ghana list TCP/IP, LAN setup and network configuration. Understanding IP addresses lets you read what a device is telling you and fix it quickly.
What an IP address is
An IP address identifies a device on a network, like a house number on a street. The common kind, IPv4, is four numbers from 0 to 255 separated by dots, for example 192.168.1.25. A newer kind, IPv6, uses longer addresses with letters and colons; you will see both in settings.
Private and public addresses
- Private addresses are used inside a building's network. They usually start with
192.168.,10.or172.16.to172.31.. The same private addresses are reused in millions of homes and offices, which is fine because they never appear on the internet directly. - Public addresses are given by your internet provider and are what the wider internet sees. The router translates between the private addresses inside and the public address outside. This is called NAT (network address translation).