PAT (NAT Overload)
PAT (aka NAT overload) translates both IP address and the port number (if necessary).
By using a unique port number for each communication flow, a single public IP address can be used by many different internal hosts. (port number are 16 bits = over 65,000 available port numbers).
The router will keep track of which inside local address is using which inside global address and port.
Because many inside hosts can share a single public IP, PAT is very useful for preserving public IP addresses, and it is used in networks all over the world.
Configuration
Same configurations as before, but with overload
specified at the end as such
This configures PAT by mapping the ACL to the pool.
An alternative to the previous method, is mapping the ACL to the interface.
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