21.252.0.0/18
PublicClass A — /18 prefix — 16,382 usable hosts
Network address — the base address of the block (21.252.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 21.252.63.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 16,382 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.192.0 is the dotted-decimal equivalent of /18. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 21.252.0.0/18 |
| Network Address | 21.252.0.0 |
| Broadcast Address | 21.252.63.255 |
| Subnet Mask | 255.255.192.0 |
| Wildcard Mask | 0.0.63.255 |
| Prefix Length | /18 |
| IP Address Class | Class A |
| Total IP Addresses | 16,384 |
| Usable Host Addresses | 16,382 |
| First Usable IP | 21.252.0.1 |
| Last Usable IP | 21.252.63.254 |
| Network (Hex) | 0x15FC0000 |
| Broadcast (Hex) | 0x15FC3FFF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 18 bits (1s in the mask) identify the network. The remaining 14 bits identify hosts within the network.
Split into Equal Subnets
Split 21.252.0.0/18 into 2 equal /19 subnets (8,190 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 21.252.0.0/19 | 21.252.0.0 | 21.252.0.1 | 21.252.31.254 | 21.252.31.255 | 8,190 |
| 2 | 21.252.32.0/19 | 21.252.32.0 | 21.252.32.1 | 21.252.63.254 | 21.252.63.255 | 8,190 |
Split 21.252.0.0/18 into 4 equal /20 subnets (4,094 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 21.252.0.0/20 | 21.252.0.0 | 21.252.0.1 | 21.252.15.254 | 21.252.15.255 | 4,094 |
| 2 | 21.252.16.0/20 | 21.252.16.0 | 21.252.16.1 | 21.252.31.254 | 21.252.31.255 | 4,094 |
| 3 | 21.252.32.0/20 | 21.252.32.0 | 21.252.32.1 | 21.252.47.254 | 21.252.47.255 | 4,094 |
| 4 | 21.252.48.0/20 | 21.252.48.0 | 21.252.48.1 | 21.252.63.254 | 21.252.63.255 | 4,094 |
Split 21.252.0.0/18 into 8 equal /21 subnets (2,046 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 21.252.0.0/21 | 21.252.0.0 | 21.252.0.1 | 21.252.7.254 | 21.252.7.255 | 2,046 |
| 2 | 21.252.8.0/21 | 21.252.8.0 | 21.252.8.1 | 21.252.15.254 | 21.252.15.255 | 2,046 |
| 3 | 21.252.16.0/21 | 21.252.16.0 | 21.252.16.1 | 21.252.23.254 | 21.252.23.255 | 2,046 |
| 4 | 21.252.24.0/21 | 21.252.24.0 | 21.252.24.1 | 21.252.31.254 | 21.252.31.255 | 2,046 |
| 5 | 21.252.32.0/21 | 21.252.32.0 | 21.252.32.1 | 21.252.39.254 | 21.252.39.255 | 2,046 |
| 6 | 21.252.40.0/21 | 21.252.40.0 | 21.252.40.1 | 21.252.47.254 | 21.252.47.255 | 2,046 |
| 7 | 21.252.48.0/21 | 21.252.48.0 | 21.252.48.1 | 21.252.55.254 | 21.252.55.255 | 2,046 |
| 8 | 21.252.56.0/21 | 21.252.56.0 | 21.252.56.1 | 21.252.63.254 | 21.252.63.255 | 2,046 |
Split 21.252.0.0/18 into 16 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 21.252.0.0/22 | 21.252.0.0 | 21.252.0.1 | 21.252.3.254 | 21.252.3.255 | 1,022 |
| 2 | 21.252.4.0/22 | 21.252.4.0 | 21.252.4.1 | 21.252.7.254 | 21.252.7.255 | 1,022 |
| 3 | 21.252.8.0/22 | 21.252.8.0 | 21.252.8.1 | 21.252.11.254 | 21.252.11.255 | 1,022 |
| 4 | 21.252.12.0/22 | 21.252.12.0 | 21.252.12.1 | 21.252.15.254 | 21.252.15.255 | 1,022 |
| 5 | 21.252.16.0/22 | 21.252.16.0 | 21.252.16.1 | 21.252.19.254 | 21.252.19.255 | 1,022 |
| 6 | 21.252.20.0/22 | 21.252.20.0 | 21.252.20.1 | 21.252.23.254 | 21.252.23.255 | 1,022 |
| 7 | 21.252.24.0/22 | 21.252.24.0 | 21.252.24.1 | 21.252.27.254 | 21.252.27.255 | 1,022 |
| 8 | 21.252.28.0/22 | 21.252.28.0 | 21.252.28.1 | 21.252.31.254 | 21.252.31.255 | 1,022 |
| 9 | 21.252.32.0/22 | 21.252.32.0 | 21.252.32.1 | 21.252.35.254 | 21.252.35.255 | 1,022 |
| 10 | 21.252.36.0/22 | 21.252.36.0 | 21.252.36.1 | 21.252.39.254 | 21.252.39.255 | 1,022 |
| 11 | 21.252.40.0/22 | 21.252.40.0 | 21.252.40.1 | 21.252.43.254 | 21.252.43.255 | 1,022 |
| 12 | 21.252.44.0/22 | 21.252.44.0 | 21.252.44.1 | 21.252.47.254 | 21.252.47.255 | 1,022 |
| 13 | 21.252.48.0/22 | 21.252.48.0 | 21.252.48.1 | 21.252.51.254 | 21.252.51.255 | 1,022 |
| 14 | 21.252.52.0/22 | 21.252.52.0 | 21.252.52.1 | 21.252.55.254 | 21.252.55.255 | 1,022 |
| 15 | 21.252.56.0/22 | 21.252.56.0 | 21.252.56.1 | 21.252.59.254 | 21.252.59.255 | 1,022 |
| 16 | 21.252.60.0/22 | 21.252.60.0 | 21.252.60.1 | 21.252.63.254 | 21.252.63.255 | 1,022 |