Which NAT variant is used for Internet sharing when the ISP IP is assigned dynamically?

Which NAT variant is used for Internet sharing when the ISP IP is assigned dynamically?

• A. Masquerade
• B. NAT
• C. Simple Queue
• D. Queues

Answer: (A)

Masquerade is the NAT variant designed for situations where the public IP can change. It works as a dynamic source NAT: the translated (outgoing) address uses the current IP on the outbound interface, and it updates automatically whenever that ISP-assigned IP changes. This makes it ideal for Internet sharing with DHCP or PPPoE connections, where the public address may be reassigned without any NAT rule adjustment. In contrast, a NAT rule that relies on a fixed external IP would break whenever the ISP changes the IP. The other options are not NAT functions and won’t perform address translation for Internet sharing.

Masquerade is the NAT variant designed for situations where the public IP can change. It works as a dynamic source NAT: the translated (outgoing) address uses the current IP on the outbound interface, and it updates automatically whenever that ISP-assigned IP changes. This makes it ideal for Internet sharing with DHCP or PPPoE connections, where the public address may be reassigned without any NAT rule adjustment. In contrast, a NAT rule that relies on a fixed external IP would break whenever the ISP changes the IP. The other options are not NAT functions and won’t perform address translation for Internet sharing.