Explain the difference between static NAT, dynamic NAT, and PAT.

Explain the difference between static NAT, dynamic NAT, and PAT.

• A. Static NAT maps a private IP to a fixed public IP; dynamic NAT uses a pool of public IPs; PAT maps many private IPs to a single public IP using unique port mappings.
• B. Static NAT maps private IPs to a pool of public IPs; dynamic NAT maps many private IPs to a single public IP; PAT uses port ranges for private IPs.
• C. Static NAT uses a pool of public IPs to map multiple private IPs; dynamic NAT maps a private IP to a fixed public IP; PAT maps only the host portion.
• D. PAT maps private IPs to multiple public IPs; static NAT uses a single public IP.

Answer: (A)

NAT variants differ in how they map internal private addresses to public ones. Static NAT provides a fixed, one-to-one mapping between a private IP and a public IP, so that host always appears as the same public address. Dynamic NAT uses a pool of public IP addresses and assigns one from the pool when a private host needs access; the mapping exists only for the duration of the session and the public IP is released afterward. PAT (NAT overloading) lets many private IPs share a single public IP by using different source port numbers to keep each connection distinct, effectively multiplexing many internal addresses over one public address. This description matches the standard definitions: a fixed private-to-public mapping for static NAT, a pool-based assignment for dynamic NAT, and port-based multiplexing on a single public IP for PAT. The other statements mix up these behaviors—static NAT isn’t a pool, dynamic NAT isn’t limited to a single public IP, and PAT relies on port numbers to distinguish connections rather than using multiple public addresses.

NAT variants differ in how they map internal private addresses to public ones. Static NAT provides a fixed, one-to-one mapping between a private IP and a public IP, so that host always appears as the same public address. Dynamic NAT uses a pool of public IP addresses and assigns one from the pool when a private host needs access; the mapping exists only for the duration of the session and the public IP is released afterward. PAT (NAT overloading) lets many private IPs share a single public IP by using different source port numbers to keep each connection distinct, effectively multiplexing many internal addresses over one public address.

This description matches the standard definitions: a fixed private-to-public mapping for static NAT, a pool-based assignment for dynamic NAT, and port-based multiplexing on a single public IP for PAT. The other statements mix up these behaviors—static NAT isn’t a pool, dynamic NAT isn’t limited to a single public IP, and PAT relies on port numbers to distinguish connections rather than using multiple public addresses.