178.12.128.0/20
PublicClass B — /20 prefix — 4,094 usable hosts
Network address — the base address of the block (178.12.128.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 178.12.143.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 4,094 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.240.0 is the dotted-decimal equivalent of /20. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 178.12.128.0/20 |
| Network Address | 178.12.128.0 |
| Broadcast Address | 178.12.143.255 |
| Subnet Mask | 255.255.240.0 |
| Wildcard Mask | 0.0.15.255 |
| Prefix Length | /20 |
| IP Address Class | Class B |
| Total IP Addresses | 4,096 |
| Usable Host Addresses | 4,094 |
| First Usable IP | 178.12.128.1 |
| Last Usable IP | 178.12.143.254 |
| Network (Hex) | 0xB20C8000 |
| Broadcast (Hex) | 0xB20C8FFF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 20 bits (1s in the mask) identify the network. The remaining 12 bits identify hosts within the network.
Split into Equal Subnets
Split 178.12.128.0/20 into 2 equal /21 subnets (2,046 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 178.12.128.0/21 | 178.12.128.0 | 178.12.128.1 | 178.12.135.254 | 178.12.135.255 | 2,046 |
| 2 | 178.12.136.0/21 | 178.12.136.0 | 178.12.136.1 | 178.12.143.254 | 178.12.143.255 | 2,046 |
Split 178.12.128.0/20 into 4 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 178.12.128.0/22 | 178.12.128.0 | 178.12.128.1 | 178.12.131.254 | 178.12.131.255 | 1,022 |
| 2 | 178.12.132.0/22 | 178.12.132.0 | 178.12.132.1 | 178.12.135.254 | 178.12.135.255 | 1,022 |
| 3 | 178.12.136.0/22 | 178.12.136.0 | 178.12.136.1 | 178.12.139.254 | 178.12.139.255 | 1,022 |
| 4 | 178.12.140.0/22 | 178.12.140.0 | 178.12.140.1 | 178.12.143.254 | 178.12.143.255 | 1,022 |
Split 178.12.128.0/20 into 8 equal /23 subnets (510 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 178.12.128.0/23 | 178.12.128.0 | 178.12.128.1 | 178.12.129.254 | 178.12.129.255 | 510 |
| 2 | 178.12.130.0/23 | 178.12.130.0 | 178.12.130.1 | 178.12.131.254 | 178.12.131.255 | 510 |
| 3 | 178.12.132.0/23 | 178.12.132.0 | 178.12.132.1 | 178.12.133.254 | 178.12.133.255 | 510 |
| 4 | 178.12.134.0/23 | 178.12.134.0 | 178.12.134.1 | 178.12.135.254 | 178.12.135.255 | 510 |
| 5 | 178.12.136.0/23 | 178.12.136.0 | 178.12.136.1 | 178.12.137.254 | 178.12.137.255 | 510 |
| 6 | 178.12.138.0/23 | 178.12.138.0 | 178.12.138.1 | 178.12.139.254 | 178.12.139.255 | 510 |
| 7 | 178.12.140.0/23 | 178.12.140.0 | 178.12.140.1 | 178.12.141.254 | 178.12.141.255 | 510 |
| 8 | 178.12.142.0/23 | 178.12.142.0 | 178.12.142.1 | 178.12.143.254 | 178.12.143.255 | 510 |
Split 178.12.128.0/20 into 16 equal /24 subnets (254 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 178.12.128.0/24 | 178.12.128.0 | 178.12.128.1 | 178.12.128.254 | 178.12.128.255 | 254 |
| 2 | 178.12.129.0/24 | 178.12.129.0 | 178.12.129.1 | 178.12.129.254 | 178.12.129.255 | 254 |
| 3 | 178.12.130.0/24 | 178.12.130.0 | 178.12.130.1 | 178.12.130.254 | 178.12.130.255 | 254 |
| 4 | 178.12.131.0/24 | 178.12.131.0 | 178.12.131.1 | 178.12.131.254 | 178.12.131.255 | 254 |
| 5 | 178.12.132.0/24 | 178.12.132.0 | 178.12.132.1 | 178.12.132.254 | 178.12.132.255 | 254 |
| 6 | 178.12.133.0/24 | 178.12.133.0 | 178.12.133.1 | 178.12.133.254 | 178.12.133.255 | 254 |
| 7 | 178.12.134.0/24 | 178.12.134.0 | 178.12.134.1 | 178.12.134.254 | 178.12.134.255 | 254 |
| 8 | 178.12.135.0/24 | 178.12.135.0 | 178.12.135.1 | 178.12.135.254 | 178.12.135.255 | 254 |
| 9 | 178.12.136.0/24 | 178.12.136.0 | 178.12.136.1 | 178.12.136.254 | 178.12.136.255 | 254 |
| 10 | 178.12.137.0/24 | 178.12.137.0 | 178.12.137.1 | 178.12.137.254 | 178.12.137.255 | 254 |
| 11 | 178.12.138.0/24 | 178.12.138.0 | 178.12.138.1 | 178.12.138.254 | 178.12.138.255 | 254 |
| 12 | 178.12.139.0/24 | 178.12.139.0 | 178.12.139.1 | 178.12.139.254 | 178.12.139.255 | 254 |
| 13 | 178.12.140.0/24 | 178.12.140.0 | 178.12.140.1 | 178.12.140.254 | 178.12.140.255 | 254 |
| 14 | 178.12.141.0/24 | 178.12.141.0 | 178.12.141.1 | 178.12.141.254 | 178.12.141.255 | 254 |
| 15 | 178.12.142.0/24 | 178.12.142.0 | 178.12.142.1 | 178.12.142.254 | 178.12.142.255 | 254 |
| 16 | 178.12.143.0/24 | 178.12.143.0 | 178.12.143.1 | 178.12.143.254 | 178.12.143.255 | 254 |