Dictionary · Networking Fundamentals
NAT
NAT — Network Address Translation
Addressing · Intermediate
A rewrite of addresses, and often port numbers, as packets cross between networks. Home routers use it so many private hosts can share one public address.
The router remembers which internal device started a conversation and rewrites the return traffic back to that device. It saves public addresses, but it is not a complete security control.
Picture it
The router remembers which internal device started the conversation and rewrites the return traffic. Translation is not the same thing as a firewall policy.
Example: A laptop at 192.168.1.25 appears on the Internet as 203.0.113.8 while the home router tracks the translation.
Common misconception
- Translation is not the same as a firewall policy. A host can be translated and still be exposed by an explicit forwarding rule.