What does Port Address Translation (PAT) allow multiple devices to do?

Port Address Translation (PAT) is a type of Network Address Translation (NAT) that enables multiple devices on a local network to share a single public IP address for accessing the internet. This functionality is particularly useful in environments where IP addresses are limited, as it allows for efficient use of the available address space.

When devices on a private network send packets to the internet, PAT modifies the source IP address of these packets to the public IP address while also changing the port number. This way, the router can track which internal device initiated the request by maintaining a mapping between the local IP addresses and the respective port numbers. Therefore, multiple devices can simultaneously communicate over the internet while appearing to external entities as if they are using the same public IP address.

This sharing capability provided by PAT helps conserve the number of public IP addresses that an organization needs, making it a widely adopted solution in both home and enterprise networking environments.