/0 subnet (0.0.0.0)
A /0 network has 4,294,967,296 addresses, of which 4,294,967,294 can be given to hosts after the network and broadcast addresses. Every IPv4 address. Used as the default route (0.0.0.0/0) and in “any” firewall rules.
- CIDR notation
- /0
- Subnet mask
- 0.0.0.0
- Wildcard mask
- 255.255.255.255
- Binary mask
- 00000000.00000000.00000000.00000000
- Total addresses
- 4,294,967,296
- Usable hosts
- 4,294,967,294
- Example network
- 0.0.0.0/0
- Example usable range
- 0.0.0.1 – 255.255.255.254
- /24 networks in a /0
- 16,777,216
Calculate a /0 for your own address
In firewall rules and investigations
A /0 matches every address. In a firewall rule it means “any”, so an allow rule with a /0 source is open to the whole internet.