A pool of public IP addresses is shared among private hosts on a first-come, first-served basis. No permanent mapping.

A pool of public IP addresses is shared among private hosts on a first-come, first-served basis. No permanent mapping.

• A. Static NAT
• B. PAT Port Address Translation
• C. NAT Network Address Translation
• D. Dynamic NAT

Answer: (D)

Dynamic NAT uses a pool of public addresses that are shared by private hosts. When a private host initiates traffic to outside networks, the router assigns an available public IP from that pool for the session, creating a temporary, on-demand mapping. This mapping isn’t permanent; it can be reused by other hosts once the session ends or times out. That on-demand, non-permanent assignment from a public address pool describes the scenario perfectly. Static NAT would keep a fixed private-to-public mapping, which contradicts “no permanent mapping.” PAT (Port Address Translation) typically uses a single public IP and differentiates internal hosts by port numbers rather than sharing a pool of multiple public addresses. The term in the third option isn’t the behavior described here.

Dynamic NAT uses a pool of public addresses that are shared by private hosts. When a private host initiates traffic to outside networks, the router assigns an available public IP from that pool for the session, creating a temporary, on-demand mapping. This mapping isn’t permanent; it can be reused by other hosts once the session ends or times out. That on-demand, non-permanent assignment from a public address pool describes the scenario perfectly.

Static NAT would keep a fixed private-to-public mapping, which contradicts “no permanent mapping.” PAT (Port Address Translation) typically uses a single public IP and differentiates internal hosts by port numbers rather than sharing a pool of multiple public addresses. The term in the third option isn’t the behavior described here.