NAT (Network Address Translation)

NAT (Network Address Translation) is a networking technique that allows devices with private IP addresses to access the Internet using a public IP address.

• Conserves public IP addresses
• Provides basic security
• Allows private networks to access the Internet
• Used in homes, offices, and enterprises

1. Private device sends traffic to the router
2. Router replaces private IP with public IP
3. Response returns to router
4. Router maps traffic back to private device

• Static NAT – One private IP to one public IP
• Dynamic NAT – Pool of public IPs
• PAT (NAT Overload) – Many devices share one public IP

In home and office networks, routers use PAT to allow multiple devices like laptops and phones to access the Internet using a single public IP address.