How do IPv4 and IPv6 differ?

• A. IPv4 uses 32-bit addresses; IPv6 uses 128-bit addresses and provides many more possible addresses.
• B. IPv4 uses 128-bit addresses; IPv6 uses 32-bit.
• C. IPv4 addresses are symbolic; IPv6 are numeric only.
• D. IPv4 guarantees privacy; IPv6 does not.

Answer: (A)

The main idea here is how many unique addresses each protocol can support, which comes from the length of the address itself. IPv4 uses 32-bit addresses, giving about 4.29 billion possible addresses. IPv6 uses 128-bit addresses, providing an immense number of possible addresses (2^128). This larger address space was designed to accommodate the growing number of devices on the internet and to improve routing and auto-configuration. IPv6 addresses are written using hexadecimal groups separated by colons, unlike IPv4’s dotted decimal format. The other statements don’t fit because they misstate the bit lengths or make claims about privacy that aren’t the defining difference.