About IPv4 Subnetting & CIDR
Subnetting is the practice of dividing a network into two or more smaller networks. This improves network performance, enhances security, and allows for more efficient use of the limited IPv4 address space.
Understanding CIDR Notation
CIDR (Classless Inter-Domain Routing) replaced the old Class A, B, and C network system. It uses a slash followed by a number (like /24) to represent the number of bits used for the network prefix. A /24 network provides 256 addresses, of which 254 are usable for hosts.
Usable Host Capacity
Every subnet reserves two addresses: the Network Address (the first address) and the Broadcast Address (the last address). This is why a /24 subnet has 254 usable host addresses. Use our subnet calculator to quickly plan your network topology.