A /8 fixes only the first octet, leaving 24 bits for hosts: more than 16 million addresses. It’s the old Class A size. You meet it in two places on a Mac: 127.0.0.0/8 is the loopback range (127.0.0.1 is localhost), and 10.0.0.0/8 is the largest private range from RFC 1918, used by corporate networks and VPNs. IANA also hands out public IPv4 space to the regional internet registries in /8 blocks.
Facts
- Prefix
- /8
- Subnet mask
- 255.0.0.0
- Wildcard mask
- 0.255.255.255
- Binary mask
- 11111111.00000000.00000000.00000000
- Total addresses
- 16,777,216
- Usable hosts
- 16,777,214
- Example range
- 10.0.0.0/8: 10.0.0.0 – 10.255.255.255
- Typical use
- The size of the private 10.0.0.0/8 range, loopback (127.0.0.0/8) and the old Class A blocks.
Try it
Try: , ,
- CIDR block
- 10.0.0.0/8
- IP range
- 10.0.0.0 – 10.255.255.255
- Addresses
- 16,777,216
- Usable hosts
- 16,777,214
- Subnet mask
- 255.0.0.0
- Wildcard mask
- 0.255.255.255
Neighbours: /9
Frequently asked questions
How many hosts are in a /8?
A /8 has 16,777,216 addresses. Subtracting the network and broadcast addresses leaves 16,777,214 usable hosts.
What is the subnet mask for /8?
/8 is 255.0.0.0 (wildcard mask 0.255.255.255). In binary that’s 8 ones followed by 24 zeros.