151.7.56.0/21
PublicClass B — /21 prefix — 2,046 usable hosts
Network address — the base address of the block (151.7.56.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 151.7.63.255 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 | 151.7.56.0/21 |
| Network Address | 151.7.56.0 |
| Broadcast Address | 151.7.63.255 |
| 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 | 151.7.56.1 |
| Last Usable IP | 151.7.63.254 |
| Network (Hex) | 0x97073800 |
| Broadcast (Hex) | 0x97073FFF |
| 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 151.7.56.0/21 into 2 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.7.56.0/22 | 151.7.56.0 | 151.7.56.1 | 151.7.59.254 | 151.7.59.255 | 1,022 |
| 2 | 151.7.60.0/22 | 151.7.60.0 | 151.7.60.1 | 151.7.63.254 | 151.7.63.255 | 1,022 |
Split 151.7.56.0/21 into 4 equal /23 subnets (510 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.7.56.0/23 | 151.7.56.0 | 151.7.56.1 | 151.7.57.254 | 151.7.57.255 | 510 |
| 2 | 151.7.58.0/23 | 151.7.58.0 | 151.7.58.1 | 151.7.59.254 | 151.7.59.255 | 510 |
| 3 | 151.7.60.0/23 | 151.7.60.0 | 151.7.60.1 | 151.7.61.254 | 151.7.61.255 | 510 |
| 4 | 151.7.62.0/23 | 151.7.62.0 | 151.7.62.1 | 151.7.63.254 | 151.7.63.255 | 510 |
Split 151.7.56.0/21 into 8 equal /24 subnets (254 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.7.56.0/24 | 151.7.56.0 | 151.7.56.1 | 151.7.56.254 | 151.7.56.255 | 254 |
| 2 | 151.7.57.0/24 | 151.7.57.0 | 151.7.57.1 | 151.7.57.254 | 151.7.57.255 | 254 |
| 3 | 151.7.58.0/24 | 151.7.58.0 | 151.7.58.1 | 151.7.58.254 | 151.7.58.255 | 254 |
| 4 | 151.7.59.0/24 | 151.7.59.0 | 151.7.59.1 | 151.7.59.254 | 151.7.59.255 | 254 |
| 5 | 151.7.60.0/24 | 151.7.60.0 | 151.7.60.1 | 151.7.60.254 | 151.7.60.255 | 254 |
| 6 | 151.7.61.0/24 | 151.7.61.0 | 151.7.61.1 | 151.7.61.254 | 151.7.61.255 | 254 |
| 7 | 151.7.62.0/24 | 151.7.62.0 | 151.7.62.1 | 151.7.62.254 | 151.7.62.255 | 254 |
| 8 | 151.7.63.0/24 | 151.7.63.0 | 151.7.63.1 | 151.7.63.254 | 151.7.63.255 | 254 |
Split 151.7.56.0/21 into 16 equal /25 subnets (126 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.7.56.0/25 | 151.7.56.0 | 151.7.56.1 | 151.7.56.126 | 151.7.56.127 | 126 |
| 2 | 151.7.56.128/25 | 151.7.56.128 | 151.7.56.129 | 151.7.56.254 | 151.7.56.255 | 126 |
| 3 | 151.7.57.0/25 | 151.7.57.0 | 151.7.57.1 | 151.7.57.126 | 151.7.57.127 | 126 |
| 4 | 151.7.57.128/25 | 151.7.57.128 | 151.7.57.129 | 151.7.57.254 | 151.7.57.255 | 126 |
| 5 | 151.7.58.0/25 | 151.7.58.0 | 151.7.58.1 | 151.7.58.126 | 151.7.58.127 | 126 |
| 6 | 151.7.58.128/25 | 151.7.58.128 | 151.7.58.129 | 151.7.58.254 | 151.7.58.255 | 126 |
| 7 | 151.7.59.0/25 | 151.7.59.0 | 151.7.59.1 | 151.7.59.126 | 151.7.59.127 | 126 |
| 8 | 151.7.59.128/25 | 151.7.59.128 | 151.7.59.129 | 151.7.59.254 | 151.7.59.255 | 126 |
| 9 | 151.7.60.0/25 | 151.7.60.0 | 151.7.60.1 | 151.7.60.126 | 151.7.60.127 | 126 |
| 10 | 151.7.60.128/25 | 151.7.60.128 | 151.7.60.129 | 151.7.60.254 | 151.7.60.255 | 126 |
| 11 | 151.7.61.0/25 | 151.7.61.0 | 151.7.61.1 | 151.7.61.126 | 151.7.61.127 | 126 |
| 12 | 151.7.61.128/25 | 151.7.61.128 | 151.7.61.129 | 151.7.61.254 | 151.7.61.255 | 126 |
| 13 | 151.7.62.0/25 | 151.7.62.0 | 151.7.62.1 | 151.7.62.126 | 151.7.62.127 | 126 |
| 14 | 151.7.62.128/25 | 151.7.62.128 | 151.7.62.129 | 151.7.62.254 | 151.7.62.255 | 126 |
| 15 | 151.7.63.0/25 | 151.7.63.0 | 151.7.63.1 | 151.7.63.126 | 151.7.63.127 | 126 |
| 16 | 151.7.63.128/25 | 151.7.63.128 | 151.7.63.129 | 151.7.63.254 | 151.7.63.255 | 126 |