ICND1 – NAT/PAT
Note: If you are not sure about NAT/PAT, please read my Network Address Translation NAT Tutorial.
Port Address Translation (PAT) can support thousands of users connect to the Internet using only one real global IP address. With PAT, each computer will be assigned a separate port number so that the router can identify which computer should receive the return traffic.
The keyword “overload” specifies we are using NAT Overload (PAT) in which multiple internal hosts will use only one IP address to access external network resources.
On the interface connecting to the Internet of the router we have to use the command “ip nat outside” for NAT to work. It identifies that interface as the outside interface.