Private IP addresses are reserved ranges used within local networks, such as your home or office, that cannot be routed over the public internet. These addresses allow multiple devices to communicate internally without consuming public IP space.
The three main private IP ranges are:
- 10.0.0.0/8 (10.0.0.0 – 10.255.255.255)
- 172.16.0.0/12 (172.16.0.0 – 172.31.255.255)
- 192.168.0.0/16 (192.168.0.0 – 192.168.255.255)
Devices on a local network are assigned private IPs by a router via DHCP. When they need to access the internet, the router performs Network Address Translation (NAT) to map the private IP to the router's public IP. This conserves public IPv4 addresses and adds a layer of security.
Private IPs are essential for home and business networks, enabling many devices to share a single internet connection. They are not unique globally, so the same private range can be used in countless networks without conflict.
Key takeaway: Think of private IPs like internal extensions in an office — they work within the building but need a receptionist (NAT) to connect to the outside world.