178.66.21.224/28
PublicClass B — /28 prefix — 14 usable hosts
Network address — the base address of the block (178.66.21.224). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 178.66.21.239 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 14 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.255.240 is the dotted-decimal equivalent of /28. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 178.66.21.224/28 |
| Network Address | 178.66.21.224 |
| Broadcast Address | 178.66.21.239 |
| Subnet Mask | 255.255.255.240 |
| Wildcard Mask | 0.0.0.15 |
| Prefix Length | /28 |
| IP Address Class | Class B |
| Total IP Addresses | 16 |
| Usable Host Addresses | 14 |
| First Usable IP | 178.66.21.225 |
| Last Usable IP | 178.66.21.238 |
| Network (Hex) | 0xB24215E0 |
| Broadcast (Hex) | 0xB24215EF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 28 bits (1s in the mask) identify the network. The remaining 4 bits identify hosts within the network.
Split into Equal Subnets
Split 178.66.21.224/28 into 2 equal /29 subnets (6 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 178.66.21.224/29 | 178.66.21.224 | 178.66.21.225 | 178.66.21.230 | 178.66.21.231 | 6 |
| 2 | 178.66.21.232/29 | 178.66.21.232 | 178.66.21.233 | 178.66.21.238 | 178.66.21.239 | 6 |
Split 178.66.21.224/28 into 4 equal /30 subnets (2 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 178.66.21.224/30 | 178.66.21.224 | 178.66.21.225 | 178.66.21.226 | 178.66.21.227 | 2 |
| 2 | 178.66.21.228/30 | 178.66.21.228 | 178.66.21.229 | 178.66.21.230 | 178.66.21.231 | 2 |
| 3 | 178.66.21.232/30 | 178.66.21.232 | 178.66.21.233 | 178.66.21.234 | 178.66.21.235 | 2 |
| 4 | 178.66.21.236/30 | 178.66.21.236 | 178.66.21.237 | 178.66.21.238 | 178.66.21.239 | 2 |