CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and routing. The notation combines an IP address with a suffix indicating how many bits are used for the network portion.
Understanding CIDR Notation
- /8: 16,777,214 usable hosts (Class A equivalent)
- /16: 65,534 usable hosts (Class B equivalent)
- /24: 254 usable hosts (Class C equivalent)
- /32: Single host address
Common Use Cases
- Network Planning: Determine how many hosts a subnet can accommodate.
- Firewall Rules: Define IP ranges for access control lists.
- VPN Configuration: Specify which networks to route through the tunnel.
- Cloud Networking: Configure VPC subnets and security groups.