151.7.104.0/21
PublicClass B — /21 prefix — 2,046 usable hosts
Network address — the base address of the block (151.7.104.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 151.7.111.255 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 | 151.7.104.0/21 |
| Network Address | 151.7.104.0 |
| Broadcast Address | 151.7.111.255 |
| 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 | 151.7.104.1 |
| Last Usable IP | 151.7.111.254 |
| Network (Hex) | 0x97076800 |
| Broadcast (Hex) | 0x97076FFF |
| 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 151.7.104.0/21 into 2 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.7.104.0/22 | 151.7.104.0 | 151.7.104.1 | 151.7.107.254 | 151.7.107.255 | 1,022 |
| 2 | 151.7.108.0/22 | 151.7.108.0 | 151.7.108.1 | 151.7.111.254 | 151.7.111.255 | 1,022 |
Split 151.7.104.0/21 into 4 equal /23 subnets (510 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.7.104.0/23 | 151.7.104.0 | 151.7.104.1 | 151.7.105.254 | 151.7.105.255 | 510 |
| 2 | 151.7.106.0/23 | 151.7.106.0 | 151.7.106.1 | 151.7.107.254 | 151.7.107.255 | 510 |
| 3 | 151.7.108.0/23 | 151.7.108.0 | 151.7.108.1 | 151.7.109.254 | 151.7.109.255 | 510 |
| 4 | 151.7.110.0/23 | 151.7.110.0 | 151.7.110.1 | 151.7.111.254 | 151.7.111.255 | 510 |
Split 151.7.104.0/21 into 8 equal /24 subnets (254 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.7.104.0/24 | 151.7.104.0 | 151.7.104.1 | 151.7.104.254 | 151.7.104.255 | 254 |
| 2 | 151.7.105.0/24 | 151.7.105.0 | 151.7.105.1 | 151.7.105.254 | 151.7.105.255 | 254 |
| 3 | 151.7.106.0/24 | 151.7.106.0 | 151.7.106.1 | 151.7.106.254 | 151.7.106.255 | 254 |
| 4 | 151.7.107.0/24 | 151.7.107.0 | 151.7.107.1 | 151.7.107.254 | 151.7.107.255 | 254 |
| 5 | 151.7.108.0/24 | 151.7.108.0 | 151.7.108.1 | 151.7.108.254 | 151.7.108.255 | 254 |
| 6 | 151.7.109.0/24 | 151.7.109.0 | 151.7.109.1 | 151.7.109.254 | 151.7.109.255 | 254 |
| 7 | 151.7.110.0/24 | 151.7.110.0 | 151.7.110.1 | 151.7.110.254 | 151.7.110.255 | 254 |
| 8 | 151.7.111.0/24 | 151.7.111.0 | 151.7.111.1 | 151.7.111.254 | 151.7.111.255 | 254 |
Split 151.7.104.0/21 into 16 equal /25 subnets (126 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 151.7.104.0/25 | 151.7.104.0 | 151.7.104.1 | 151.7.104.126 | 151.7.104.127 | 126 |
| 2 | 151.7.104.128/25 | 151.7.104.128 | 151.7.104.129 | 151.7.104.254 | 151.7.104.255 | 126 |
| 3 | 151.7.105.0/25 | 151.7.105.0 | 151.7.105.1 | 151.7.105.126 | 151.7.105.127 | 126 |
| 4 | 151.7.105.128/25 | 151.7.105.128 | 151.7.105.129 | 151.7.105.254 | 151.7.105.255 | 126 |
| 5 | 151.7.106.0/25 | 151.7.106.0 | 151.7.106.1 | 151.7.106.126 | 151.7.106.127 | 126 |
| 6 | 151.7.106.128/25 | 151.7.106.128 | 151.7.106.129 | 151.7.106.254 | 151.7.106.255 | 126 |
| 7 | 151.7.107.0/25 | 151.7.107.0 | 151.7.107.1 | 151.7.107.126 | 151.7.107.127 | 126 |
| 8 | 151.7.107.128/25 | 151.7.107.128 | 151.7.107.129 | 151.7.107.254 | 151.7.107.255 | 126 |
| 9 | 151.7.108.0/25 | 151.7.108.0 | 151.7.108.1 | 151.7.108.126 | 151.7.108.127 | 126 |
| 10 | 151.7.108.128/25 | 151.7.108.128 | 151.7.108.129 | 151.7.108.254 | 151.7.108.255 | 126 |
| 11 | 151.7.109.0/25 | 151.7.109.0 | 151.7.109.1 | 151.7.109.126 | 151.7.109.127 | 126 |
| 12 | 151.7.109.128/25 | 151.7.109.128 | 151.7.109.129 | 151.7.109.254 | 151.7.109.255 | 126 |
| 13 | 151.7.110.0/25 | 151.7.110.0 | 151.7.110.1 | 151.7.110.126 | 151.7.110.127 | 126 |
| 14 | 151.7.110.128/25 | 151.7.110.128 | 151.7.110.129 | 151.7.110.254 | 151.7.110.255 | 126 |
| 15 | 151.7.111.0/25 | 151.7.111.0 | 151.7.111.1 | 151.7.111.126 | 151.7.111.127 | 126 |
| 16 | 151.7.111.128/25 | 151.7.111.128 | 151.7.111.129 | 151.7.111.254 | 151.7.111.255 | 126 |