IPv4 addresses are expressible as a 32-bit number.

IPv4 addresses are expressible as a 32-bit number.

• A. Expressible as a 16 bit number
• B. Expressible as a 64 bit number
• C. Expressible as a 32 bit number
• D. Expressible as a 128 bit number

Answer: (C)

IPv4 uses 32 bits for each address. That means an address is made up of four 8-bit parts (octets) and can take 2^32 different values, about 4.29 billion. Because of that, the natural way to express an IPv4 address in a computer is as a 32-bit number. If you used only 16 bits, you’d have only 65,536 possible addresses—far too few for the Internet. Using 64 or 128 bits isn’t necessary for IPv4 (128 bits is the size used by IPv6). The dotted-decimal form you often see is simply a human-friendly way to read the same 32-bit value.

IPv4 uses 32 bits for each address. That means an address is made up of four 8-bit parts (octets) and can take 2^32 different values, about 4.29 billion. Because of that, the natural way to express an IPv4 address in a computer is as a 32-bit number. If you used only 16 bits, you’d have only 65,536 possible addresses—far too few for the Internet. Using 64 or 128 bits isn’t necessary for IPv4 (128 bits is the size used by IPv6). The dotted-decimal form you often see is simply a human-friendly way to read the same 32-bit value.