This process modifies network address information in IP packet headers while they are in transit across a traffic routing device. One typical application involves presenting an entire group of computers behind a firewall with a single, publicly visible IP address. For example, an organization with numerous internal machines, each possessing a private address, can communicate with the outside internet through a single, registered address. This function is performed by the device that connects the internal network to the internet.
A key benefit is that it enhances security by hiding the internal addressing scheme of a network. This makes it more difficult for external entities to directly target individual devices within the protected network. Furthermore, it helps to alleviate IPv4 address exhaustion, as multiple devices can share a single public address. Historically, this technology emerged as a practical solution to address the growing demand for internet connectivity in the face of limited publicly available IP addresses.