28.40.0.0/17
PublicClass A — /17 prefix — 32,766 usable hosts
Network address — the base address of the block (28.40.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 28.40.127.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 32,766 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.128.0 is the dotted-decimal equivalent of /17. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 28.40.0.0/17 |
| Network Address | 28.40.0.0 |
| Broadcast Address | 28.40.127.255 |
| Subnet Mask | 255.255.128.0 |
| Wildcard Mask | 0.0.127.255 |
| Prefix Length | /17 |
| IP Address Class | Class A |
| Total IP Addresses | 32,768 |
| Usable Host Addresses | 32,766 |
| First Usable IP | 28.40.0.1 |
| Last Usable IP | 28.40.127.254 |
| Network (Hex) | 0x1C280000 |
| Broadcast (Hex) | 0x1C287FFF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 17 bits (1s in the mask) identify the network. The remaining 15 bits identify hosts within the network.
Split into Equal Subnets
Split 28.40.0.0/17 into 2 equal /18 subnets (16,382 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 28.40.0.0/18 | 28.40.0.0 | 28.40.0.1 | 28.40.63.254 | 28.40.63.255 | 16,382 |
| 2 | 28.40.64.0/18 | 28.40.64.0 | 28.40.64.1 | 28.40.127.254 | 28.40.127.255 | 16,382 |
Split 28.40.0.0/17 into 4 equal /19 subnets (8,190 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 28.40.0.0/19 | 28.40.0.0 | 28.40.0.1 | 28.40.31.254 | 28.40.31.255 | 8,190 |
| 2 | 28.40.32.0/19 | 28.40.32.0 | 28.40.32.1 | 28.40.63.254 | 28.40.63.255 | 8,190 |
| 3 | 28.40.64.0/19 | 28.40.64.0 | 28.40.64.1 | 28.40.95.254 | 28.40.95.255 | 8,190 |
| 4 | 28.40.96.0/19 | 28.40.96.0 | 28.40.96.1 | 28.40.127.254 | 28.40.127.255 | 8,190 |
Split 28.40.0.0/17 into 8 equal /20 subnets (4,094 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 28.40.0.0/20 | 28.40.0.0 | 28.40.0.1 | 28.40.15.254 | 28.40.15.255 | 4,094 |
| 2 | 28.40.16.0/20 | 28.40.16.0 | 28.40.16.1 | 28.40.31.254 | 28.40.31.255 | 4,094 |
| 3 | 28.40.32.0/20 | 28.40.32.0 | 28.40.32.1 | 28.40.47.254 | 28.40.47.255 | 4,094 |
| 4 | 28.40.48.0/20 | 28.40.48.0 | 28.40.48.1 | 28.40.63.254 | 28.40.63.255 | 4,094 |
| 5 | 28.40.64.0/20 | 28.40.64.0 | 28.40.64.1 | 28.40.79.254 | 28.40.79.255 | 4,094 |
| 6 | 28.40.80.0/20 | 28.40.80.0 | 28.40.80.1 | 28.40.95.254 | 28.40.95.255 | 4,094 |
| 7 | 28.40.96.0/20 | 28.40.96.0 | 28.40.96.1 | 28.40.111.254 | 28.40.111.255 | 4,094 |
| 8 | 28.40.112.0/20 | 28.40.112.0 | 28.40.112.1 | 28.40.127.254 | 28.40.127.255 | 4,094 |
Split 28.40.0.0/17 into 16 equal /21 subnets (2,046 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 28.40.0.0/21 | 28.40.0.0 | 28.40.0.1 | 28.40.7.254 | 28.40.7.255 | 2,046 |
| 2 | 28.40.8.0/21 | 28.40.8.0 | 28.40.8.1 | 28.40.15.254 | 28.40.15.255 | 2,046 |
| 3 | 28.40.16.0/21 | 28.40.16.0 | 28.40.16.1 | 28.40.23.254 | 28.40.23.255 | 2,046 |
| 4 | 28.40.24.0/21 | 28.40.24.0 | 28.40.24.1 | 28.40.31.254 | 28.40.31.255 | 2,046 |
| 5 | 28.40.32.0/21 | 28.40.32.0 | 28.40.32.1 | 28.40.39.254 | 28.40.39.255 | 2,046 |
| 6 | 28.40.40.0/21 | 28.40.40.0 | 28.40.40.1 | 28.40.47.254 | 28.40.47.255 | 2,046 |
| 7 | 28.40.48.0/21 | 28.40.48.0 | 28.40.48.1 | 28.40.55.254 | 28.40.55.255 | 2,046 |
| 8 | 28.40.56.0/21 | 28.40.56.0 | 28.40.56.1 | 28.40.63.254 | 28.40.63.255 | 2,046 |
| 9 | 28.40.64.0/21 | 28.40.64.0 | 28.40.64.1 | 28.40.71.254 | 28.40.71.255 | 2,046 |
| 10 | 28.40.72.0/21 | 28.40.72.0 | 28.40.72.1 | 28.40.79.254 | 28.40.79.255 | 2,046 |
| 11 | 28.40.80.0/21 | 28.40.80.0 | 28.40.80.1 | 28.40.87.254 | 28.40.87.255 | 2,046 |
| 12 | 28.40.88.0/21 | 28.40.88.0 | 28.40.88.1 | 28.40.95.254 | 28.40.95.255 | 2,046 |
| 13 | 28.40.96.0/21 | 28.40.96.0 | 28.40.96.1 | 28.40.103.254 | 28.40.103.255 | 2,046 |
| 14 | 28.40.104.0/21 | 28.40.104.0 | 28.40.104.1 | 28.40.111.254 | 28.40.111.255 | 2,046 |
| 15 | 28.40.112.0/21 | 28.40.112.0 | 28.40.112.1 | 28.40.119.254 | 28.40.119.255 | 2,046 |
| 16 | 28.40.120.0/21 | 28.40.120.0 | 28.40.120.1 | 28.40.127.254 | 28.40.127.255 | 2,046 |