151.78.88.0/21
PublicClass B — /21 prefix — 2,046 usable hosts
Network address — the base address of the block (151.78.88.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 151.78.95.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 2,046 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.248.0 is the dotted-decimal equivalent of /21. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 151.78.88.0/21 |
| Network Address | 151.78.88.0 |
| Broadcast Address | 151.78.95.255 |
| Subnet Mask | 255.255.248.0 |
| Wildcard Mask | 0.0.7.255 |
| Prefix Length | /21 |
| IP Address Class | Class B |
| Total IP Addresses | 2,048 |
| Usable Host Addresses | 2,046 |
| First Usable IP | 151.78.88.1 |
| Last Usable IP | 151.78.95.254 |
| Network (Hex) | 0x974E5800 |
| Broadcast (Hex) | 0x974E5FFF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 21 bits (1s in the mask) identify the network. The remaining 11 bits identify hosts within the network.
Split into Equal Subnets
Split 151.78.88.0/21 into 2 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.78.88.0/22 | 151.78.88.0 | 151.78.88.1 | 151.78.91.254 | 151.78.91.255 | 1,022 |
| 2 | 151.78.92.0/22 | 151.78.92.0 | 151.78.92.1 | 151.78.95.254 | 151.78.95.255 | 1,022 |
Split 151.78.88.0/21 into 4 equal /23 subnets (510 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.78.88.0/23 | 151.78.88.0 | 151.78.88.1 | 151.78.89.254 | 151.78.89.255 | 510 |
| 2 | 151.78.90.0/23 | 151.78.90.0 | 151.78.90.1 | 151.78.91.254 | 151.78.91.255 | 510 |
| 3 | 151.78.92.0/23 | 151.78.92.0 | 151.78.92.1 | 151.78.93.254 | 151.78.93.255 | 510 |
| 4 | 151.78.94.0/23 | 151.78.94.0 | 151.78.94.1 | 151.78.95.254 | 151.78.95.255 | 510 |
Split 151.78.88.0/21 into 8 equal /24 subnets (254 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.78.88.0/24 | 151.78.88.0 | 151.78.88.1 | 151.78.88.254 | 151.78.88.255 | 254 |
| 2 | 151.78.89.0/24 | 151.78.89.0 | 151.78.89.1 | 151.78.89.254 | 151.78.89.255 | 254 |
| 3 | 151.78.90.0/24 | 151.78.90.0 | 151.78.90.1 | 151.78.90.254 | 151.78.90.255 | 254 |
| 4 | 151.78.91.0/24 | 151.78.91.0 | 151.78.91.1 | 151.78.91.254 | 151.78.91.255 | 254 |
| 5 | 151.78.92.0/24 | 151.78.92.0 | 151.78.92.1 | 151.78.92.254 | 151.78.92.255 | 254 |
| 6 | 151.78.93.0/24 | 151.78.93.0 | 151.78.93.1 | 151.78.93.254 | 151.78.93.255 | 254 |
| 7 | 151.78.94.0/24 | 151.78.94.0 | 151.78.94.1 | 151.78.94.254 | 151.78.94.255 | 254 |
| 8 | 151.78.95.0/24 | 151.78.95.0 | 151.78.95.1 | 151.78.95.254 | 151.78.95.255 | 254 |
Split 151.78.88.0/21 into 16 equal /25 subnets (126 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.78.88.0/25 | 151.78.88.0 | 151.78.88.1 | 151.78.88.126 | 151.78.88.127 | 126 |
| 2 | 151.78.88.128/25 | 151.78.88.128 | 151.78.88.129 | 151.78.88.254 | 151.78.88.255 | 126 |
| 3 | 151.78.89.0/25 | 151.78.89.0 | 151.78.89.1 | 151.78.89.126 | 151.78.89.127 | 126 |
| 4 | 151.78.89.128/25 | 151.78.89.128 | 151.78.89.129 | 151.78.89.254 | 151.78.89.255 | 126 |
| 5 | 151.78.90.0/25 | 151.78.90.0 | 151.78.90.1 | 151.78.90.126 | 151.78.90.127 | 126 |
| 6 | 151.78.90.128/25 | 151.78.90.128 | 151.78.90.129 | 151.78.90.254 | 151.78.90.255 | 126 |
| 7 | 151.78.91.0/25 | 151.78.91.0 | 151.78.91.1 | 151.78.91.126 | 151.78.91.127 | 126 |
| 8 | 151.78.91.128/25 | 151.78.91.128 | 151.78.91.129 | 151.78.91.254 | 151.78.91.255 | 126 |
| 9 | 151.78.92.0/25 | 151.78.92.0 | 151.78.92.1 | 151.78.92.126 | 151.78.92.127 | 126 |
| 10 | 151.78.92.128/25 | 151.78.92.128 | 151.78.92.129 | 151.78.92.254 | 151.78.92.255 | 126 |
| 11 | 151.78.93.0/25 | 151.78.93.0 | 151.78.93.1 | 151.78.93.126 | 151.78.93.127 | 126 |
| 12 | 151.78.93.128/25 | 151.78.93.128 | 151.78.93.129 | 151.78.93.254 | 151.78.93.255 | 126 |
| 13 | 151.78.94.0/25 | 151.78.94.0 | 151.78.94.1 | 151.78.94.126 | 151.78.94.127 | 126 |
| 14 | 151.78.94.128/25 | 151.78.94.128 | 151.78.94.129 | 151.78.94.254 | 151.78.94.255 | 126 |
| 15 | 151.78.95.0/25 | 151.78.95.0 | 151.78.95.1 | 151.78.95.126 | 151.78.95.127 | 126 |
| 16 | 151.78.95.128/25 | 151.78.95.128 | 151.78.95.129 | 151.78.95.254 | 151.78.95.255 | 126 |