/32 Subnet
Single host address
A /32 identifies a single, specific IP address. Used in host routes, loopback interfaces, security group rules targeting one exact IP, and ACLs.
Common Use Cases
- → Host route in routing table
- → Loopback interface address
- → Security group rule for a single IP
- → BGP next-hop or router-id
Example /32 Networks
| CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|
| 10.0.0.0/32 | 10.0.0.0 | 10.0.0.0 | 10.0.0.0 | 10.0.0.0 | 1 |
| 172.16.0.0/32 | 172.16.0.0 | 172.16.0.0 | 172.16.0.0 | 172.16.0.0 | 1 |
| 172.31.0.0/32 | 172.31.0.0 | 172.31.0.0 | 172.31.0.0 | 172.31.0.0 | 1 |
| 192.168.0.0/32 | 192.168.0.0 | 192.168.0.0 | 192.168.0.0 | 192.168.0.0 | 1 |
| 192.168.1.0/32 | 192.168.1.0 | 192.168.1.0 | 192.168.1.0 | 192.168.1.0 | 1 |
| 10.0.1.0/32 | 10.0.1.0 | 10.0.1.0 | 10.0.1.0 | 10.0.1.0 | 1 |
How /32 Compares
Frequently Asked Questions
How many IPs are in a /32?
A /32 subnet contains 1 total IP addresses and 1 usable host addresses. A /32 identifies a single specific IP address (host route).
What is the subnet mask for /32?
The subnet mask for a /32 is 255.255.255.255.
In CIDR notation, the prefix length /32 means
the first 32 bits of the address are the network portion.
The wildcard (inverse) mask is 0.0.0.0.
How many /32 subnets fit in a /31?
Exactly 2 — a /31 can be split into two /32 subnets of equal size. Each /32 subnet has 1 usable hosts, compared to 2 in the parent /31.