Which statement about IPv4 addressing is true?

Which statement about IPv4 addressing is true?

• A. IPv4 addresses are 64-bit.
• B. IPv4 addresses are 16-bit.
• C. IPv4 does not support routing.
• D. IPv4 addresses are 32-bit, providing about 4.3 billion addresses.

Answer: (D)

IPv4 addresses are 32-bit numbers, which means each address is made up of four 8-bit octets. With 32 bits, there are 2^32 possible unique addresses, which is 4,294,967,296—often rounded to about 4.3 billion. That’s the scale IPv4 was designed to support for devices on networks and the Internet. The other statements miss this fundamental fact: 64-bit would yield far more addresses, 16-bit would yield only 65,536, and IPv4 is indeed designed for routing across networks (routing is a core function of IP). For context, IPv6 uses 128-bit addresses to vastly increase the available space.

IPv4 addresses are 32-bit numbers, which means each address is made up of four 8-bit octets. With 32 bits, there are 2^32 possible unique addresses, which is 4,294,967,296—often rounded to about 4.3 billion. That’s the scale IPv4 was designed to support for devices on networks and the Internet. The other statements miss this fundamental fact: 64-bit would yield far more addresses, 16-bit would yield only 65,536, and IPv4 is indeed designed for routing across networks (routing is a core function of IP). For context, IPv6 uses 128-bit addresses to vastly increase the available space.