What does the acronym PAT refer to in networking?

• A. A method for encrypting data with port-based keys.
• B. A NAT technology that translates only IP addresses, not ports.
• C. Acronym for 'port address translation' and a type of NAT that translates port numbers.
• D. A protocol for dynamic address assignment in networks.

Answer: (C)

PAT, or port address translation, is a form of NAT that not only translates private IP addresses to a public one but also translates the transport-layer port numbers. This lets many internal devices share a single public IP by giving each ongoing connection a unique public port. For example, two internal hosts can both access the same external server on port 80, but PAT maps them to the same public IP with different external ports, ensuring replies are delivered correctly to the right internal host. The other descriptions don’t fit: encrypting data with port-based keys isn’t about NAT; translating only IPs without ports is classic NAT, not PAT; and a protocol for dynamic address assignment refers to DHCP, not NAT.