What is a /23 subnet?
510 usable hosts out of 512 addresses, behind netmask 255.255.254.0.
| Prefix | /23 |
|---|---|
| Netmask | 255.255.254.0 |
| Wildcard | 0.0.1.255 |
| Total addresses | 512 |
| Usable hosts | 510 |
| Example block | 10.0.0.0/23 |
| Usable host range | 10.0.0.1 – 10.0.1.254 |
| Broadcast | 10.0.1.255 |
A /23 fixes the first 23 bits of the address as the network and leaves 9 for hosts — 512 addresses in all.
Of those, 510 can be given to a machine: the first address names the network itself, and the last is the broadcast address.
A comfortable size for a large subnet or a small site — more than a single /24, without committing a whole /16.
It is 2 times the size of a /24.
Other subnet sizes
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