/17 subnet
Mask 255.255.128.0 · 32,766 usable hosts · 32,768 addresses
| Subnet mask | 255.255.128.0 |
|---|---|
| Wildcard mask | 0.0.127.255 |
| Binary mask | 11111111.11111111.10000000.00000000 |
| Network / host bits | 17 / 15 |
| Total addresses | 32,768 |
| Usable hosts | 32,766 |
| Per /8 · /16 · /24 | 512 · 2 · – |
| Example | 192.168.10.77/17 → network 192.168.0.0, hosts 192.168.0.1 – 192.168.127.254, broadcast 192.168.127.255 |
Where /17 is used
A /17 is a less common size; it sits between /16 (65,536 addresses) and /18 (16,384 addresses).
Block boundaries: a /17 must start at a multiple of 32,768 addresses. Calculate any specific address in the subnet calculator.
Neighbouring prefixes
Questions
How many hosts in a /17?
32,768 addresses, of which 32,766 are usable (the first is the network address and the last is broadcast).
What is the subnet mask for /17?
255.255.128.0. In binary: 11111111.11111111.10000000.00000000. The wildcard (inverse) mask is 0.0.127.255.