/21 subnet
A /21 prefix equals subnet mask 255.255.248.0 and wildcard 0.0.7.255. It holds 2,048 addresses, 2,046 of them usable by hosts.
/21
- Subnet mask
- 255.255.248.0
- Wildcard mask
- 0.0.7.255
- Binary mask
- 11111111.11111111.11111000.00000000
- Total addresses
- 2,048
- Usable hosts
- 2,046
- Example network
- 10.0.0.0/21
- Example range
- 10.0.0.0 – 10.0.7.255
- How many fit
- 8,192 × /21 in a /8, 32 × /21 in a /16