How does IPv4 address exhaustion influence NAT usage and IPv6 adoption?

• A. NAT is used to conserve address space; IPv6 provides abundant addresses enabling end-to-end connectivity.
• B. NAT eliminates the need for IPv6 altogether.
• C. IPv6 adoption is slowed by NAT, so NAT remains mandatory.
• D. NAT and IPv6 are unrelated and do not affect each other.

Answer: (D)

IPv4 exhaustion drives NAT because NAT lets many devices share a single public IPv4 address, stretching limited addresses further. IPv6, with its enormous address space, lets each device have a unique public address, enabling end-to-end connectivity and reducing the need for NAT. NAT is not required in IPv6, and IPv6 adoption depends on several factors beyond NAT, such as compatibility and deployment challenges. Saying NAT and IPv6 are unrelated ignores their connected history: scarcity of IPv4 pushes NAT as a workaround, while IPv6 aims to replace NAT by providing abundant addresses for direct, end-to-end communication.