| CIDR | Subnet Mask | Wildcard Mask | Total Hosts | Usable Hosts |
|---|
Subnet MaskUsed to divide the network and host portions of an IP address. It is a 32-bit binary number where the network part is represented by 1s and the host part by 0s.
CIDR (Classless Inter-Domain Routing)A more concise way to represent subnet masks, using a slash followed by a number indicating the number of network bits. For example: 192.168.1.0/24 means the first 24 bits are the network address.
Wildcard MaskThe inverse of the subnet mask, commonly used in router ACL configurations. 0 means must match, 1 means any value.
IP Address Classes: Class A (1.0.0.0 - 126.255.255.255), Class B (128.0.0.0 - 191.255.255.255), Class C (192.0.0.0 - 223.255.255.255), Class D (224.0.0.0 - 239.255.255.255, Multicast), Class E (240.0.0.0 - 255.255.255.255, Reserved)
Private IP Address Ranges: Class A: 10.0.0.0 - 10.255.255.255, Class B: 172.16.0.0 - 172.31.255.255, Class C: 192.168.0.0 - 192.168.255.255