Which statement describes NAT's primary function?

Which statement describes NAT's primary function?

• A. Filters traffic at the firewall
• B. Remaps one IP address space into another by modifying the IP header
• C. Provides end-to-end encryption for data
• D. Assigns private IP addresses via DHCP

Answer: (B)

NAT’s primary function is to remap one IP address space into another by rewriting the IP header as traffic moves between a private network and the public Internet. When devices on a private network send outbound traffic, NAT translates the private source address (and often the source port) to a public address (and port), keeping a translation table so replies are routed back to the correct internal device. This mechanism lets many devices share a single public IP, which is the core idea behind NAT, including variants like PAT that use port translation to multiplex connections. Other options describe functions that NAT doesn’t perform: filtering traffic is a firewall task, end-to-end encryption is provided by encryption protocols, and DHCP assigns IP addresses—NAT does not handle those.

NAT’s primary function is to remap one IP address space into another by rewriting the IP header as traffic moves between a private network and the public Internet. When devices on a private network send outbound traffic, NAT translates the private source address (and often the source port) to a public address (and port), keeping a translation table so replies are routed back to the correct internal device. This mechanism lets many devices share a single public IP, which is the core idea behind NAT, including variants like PAT that use port translation to multiplex connections.

Other options describe functions that NAT doesn’t perform: filtering traffic is a firewall task, end-to-end encryption is provided by encryption protocols, and DHCP assigns IP addresses—NAT does not handle those.