Helpful Formula - theSam1998/ops-301-Reading-Notes GitHub Wiki
| Subnet Mask | CIDR Notation | Total IP Addresses | Usable IP Range | Network Address | Broadcast Address |
|---|---|---|---|---|---|
| 255.255.255.0 | /24 | 256 | 192.168.1.1 to 192.168.1.254 | 192.168.1.0 | 192.168.1.255 |
| 255.255.255.128 | /25 | 128 | 192.168.1.1 to 192.168.1.126 | 192.168.1.0 | 192.168.1.127 |
| 255.255.255.192 | /26 | 64 | 192.168.1.1 to 192.168.1.62 | 192.168.1.0 | 192.168.1.63 |
| 255.255.255.224 | /27 | 32 | 192.168.1.1 to 192.168.1.30 | 192.168.1.0 | 192.168.1.31 |
| 255.255.255.240 | /28 | 16 | 192.168.1.1 to 192.168.1.14 | 192.168.1.0 | 192.168.1.15 |
| 255.255.255.248 | /29 | 8 | 192.168.1.1 to 192.168.1.6 | 192.168.1.0 | 192.168.1.7 |
| 255.255.255.252 | /30 | 4 | 192.168.1.1 to 192.168.1.2 | 192.168.1.0 | 192.168.1.3 |
Explanation:
- Subnet Mask: The subnet mask used to divide the IP address into network and host portions.
- CIDR Notation: The CIDR notation representing the subnet mask.
- Total IP Addresses: The total number of IP addresses available in the subnet.
- Usable IP Range: The range of usable IP addresses, excluding the network and broadcast addresses.
- Network Address: The network address of the subnet.
- Broadcast Address: The broadcast address of the subnet.
Patterns:
- The network address is always the first IP address in the subnet.
- The broadcast address is always the last IP address in the subnet.
- The usable IP range excludes the network and broadcast addresses, and it starts from the second IP address and ends at the second-to-last IP address in the subnet.