How NAT Shares One Public IP
Understand how many private devices reach the internet through one address.
The Address Shortage Problem
The internet uses IPv4 addresses, of which there are only about 4.3 billion, far fewer than the number of devices online today. Buying a public address for every phone, laptop, and gadget is impossible.
NAT (Network Address Translation) is the clever fix: it lets many devices on a private network share a single public IP address to reach the internet, conserving the limited supply.
Private vs Public Addresses
Networks use private IP ranges (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16) internally. These are not routable on the public internet, so they cannot be used directly online.
A public IP address is globally unique and internet-routable. NAT bridges the two worlds, translating between private internal addresses and the public address that the internet sees.
All lessons in this course
- How NAT Shares One Public IP
- Port Forwarding and PAT
- Time and Naming Services
- Proxies and Load Balancers