A /32 matches exactly one address: mask 255.255.255.255. You don’t put devices into a /32 subnet. You use it to name a single host, for example in a firewall rule, an AWS security group (“my IP/32”), a static route, or a router’s loopback address. In SPF records, ip4:203.0.113.5 means the same as ip4:203.0.113.5/32.
Facts
- Prefix
- /32
- Subnet mask
- 255.255.255.255
- Wildcard mask
- 0.0.0.0
- Binary mask
- 11111111.11111111.11111111.11111111
- Total addresses
- 1
- Usable hosts
- 1
- Example range
- 192.168.1.0/32: 192.168.1.0 – 192.168.1.0
- Typical use
- A single host, e.g. in a routing table or a firewall rule.
Try it
Try: , ,
- CIDR block
- 192.168.1.0/32
- IP range
- 192.168.1.0 – 192.168.1.0
- Addresses
- 1
- Usable hosts
- 1
- Subnet mask
- 255.255.255.255
- Wildcard mask
- 0.0.0.0
Neighbours: /31
Frequently asked questions
How many hosts are in a /32?
A /32 has 1 address, and it identifies a single host.
What is the subnet mask for /32?
/32 is 255.255.255.255 (wildcard mask 0.0.0.0). In binary that’s 32 ones followed by 0 zeros.