Subnetting
Subnetting splits a network into smaller networks using a subnet mask/CIDR.
Updated: 2026-03-05
Definition
Subnetting is the process of dividing an IP network into smaller sub-networks to control broadcast domains and allocate addresses efficiently.
CIDR notation (like /24, /26) indicates how many bits are used for the network portion.
Key points
- CIDR determines host count per subnet
- Used for planning and routing
- Common skill for CCNA and Network+
Common mistakes
- Mixing up network/broadcast addresses and usable hosts.
- Not accounting for reserved addresses in some environments.
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