10.0.0.0/17
Private (RFC 1918) RFC 1918Class A — /17 prefix — 32,766 usable hosts
Network address — the base address of the block (10.0.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 10.0.127.255 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 | 10.0.0.0/17 |
| Network Address | 10.0.0.0 |
| Broadcast Address | 10.0.127.255 |
| 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 | 10.0.0.1 |
| Last Usable IP | 10.0.127.254 |
| Network (Hex) | 0x0A000000 |
| Broadcast (Hex) | 0x0A007FFF |
| Governing RFC | RFC 1918 |
| Address Type | Private (RFC 1918) |
Binary Representation
The first 17 bits (1s in the mask) identify the network. The remaining 15 bits identify hosts within the network.
Subnet Breakdown — splitting into /18
This /17 block can be divided into 2 /18 subnets.
| CIDR | Network | Broadcast | First Usable | Last Usable | Hosts |
|---|---|---|---|---|---|
| 10.0.0.0/18 | 10.0.0.0 | 10.0.63.255 | 10.0.0.1 | 10.0.63.254 | 16,382 |
| 10.0.64.0/18 | 10.0.64.0 | 10.0.127.255 | 10.0.64.1 | 10.0.127.254 | 16,382 |