Subnet Mask
/32 Subnet Mask
A /32 prefix means the subnet mask is 255.255.255.255. It has 0 host bits, giving 1 total addresses and 1 usable hosts.
/32 at a glance
| Property | Value |
|---|---|
| CIDR prefix | /32 |
| Subnet mask | 255.255.255.255 |
| Wildcard mask | 0.0.0.0 |
| Total addresses | 1 |
| Usable hosts | 1 (host route) |
| Host bits | 0 |
How it is calculated
A /32 sets the first 32 bits to 1 (network) and the remaining 0 bits to 0 (host). Usable hosts = 20 − 2 = 1 (special case)..
The wildcard mask 0.0.0.0 is the inverse — used in Cisco ACLs and OSPF network statements.
Frequently asked questions
What is a /32 subnet mask?
A /32 equals 255.255.255.255 in dotted decimal (wildcard 0.0.0.0). It provides 1 total addresses and 1 usable hosts.
How many hosts are in a /32?
A /32 has 0 host bits, so it supports 1 usable hosts.
What is the wildcard mask for /32?
The wildcard (inverse) mask for /32 is 0.0.0.0, used in Cisco ACLs and OSPF statements.
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