What is a /8 subnet?
16,777,214 usable hosts out of 16,777,216 addresses, behind netmask 255.0.0.0.
| Prefix | /8 |
|---|---|
| Netmask | 255.0.0.0 |
| Wildcard | 0.255.255.255 |
| Total addresses | 16,777,216 |
| Usable hosts | 16,777,214 |
| Example block | 10.0.0.0/8 |
| Usable host range | 10.0.0.1 – 10.255.255.254 |
| Broadcast | 10.255.255.255 |
A /8 fixes the first 8 bits of the address as the network and leaves 24 for hosts — 16,777,216 addresses in all.
Of those, 16,777,214 can be given to a machine: the first address names the network itself, and the last is the broadcast address.
A block this large is an allocation rather than a subnet — a whole private range to carve up, or something a regional registry hands out. You would not put hosts directly in it.
It is 65,536 times the size of a /24.
Other subnet sizes
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