What are the largest and smallest IPv4 networks you can create?

• A. /1 and /32
• B. /0 and /128
• C. /8 and /24
• D. /16 and /24

Answer: (A)

In IPv4 CIDR, network size depends on the prefix length. The shorter the prefix, the larger the network; the longer the prefix, the smaller the network. The smallest possible network is a single host, which is a /32. The largest possible subnet you’d typically create (excluding the absolute top-level /0, which represents the entire IPv4 space and is usually reserved for default routes) is a /1, which covers half the IPv4 addresses. Among the given options, /1 and /32 fit this range, making them the best pair to describe the largest and smallest IPv4 networks you can create in a standard subnetting sense. The other options either use an IPv4-incompatible prefix (like /128, which is for IPv6) or pair prefixes that don’t represent the extreme ends of subnet sizes.