IPv4 reference
IPv4 /16 prefix
IPv4 /16 prefix corresponds to /16, with 65,536 total addresses and 65,534 usable hosts.
Example network details for 0.0.0.0/16
- CIDR
- 0.0.0.0/16
- Prefix
- /16
- Network address
- 0.0.0.0
- Broadcast address
- 0.0.255.255
- First usable address
- 0.0.0.1
- Last usable address
- 0.0.255.254
- Subnet mask
- 255.255.0.0
- Wildcard mask
- 0.0.255.255
- Total addresses
- 65,536
- Usable hosts
- 65,534
Binary masks
Subnet: 11111111.11111111.00000000.00000000
Wildcard: 00000000.00000000.11111111.11111111
The first 16 bits identify the network. The remaining 16 bits identify addresses inside it.
First subdivision
Dividing this network into 4 equal blocks produces:
0.0.0.0/18— 16,382 usable hosts0.0.64.0/18— 16,382 usable hosts0.0.128.0/18— 16,382 usable hosts0.0.192.0/18— 16,382 usable hosts
Continue working with /16
What this result means
A /16 IPv4 network contains 65,536 consecutive addresses. The network and broadcast addresses are reserved in traditional LAN use, leaving 65,534 usable host addresses.
Use the wildcard mask in access lists and routing policy where a device expects inverse mask bits. Always verify vendor syntax before applying generated values to production equipment.