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.