/5 Subnet Mask
A /5 prefix means the subnet mask is 248.0.0.0. It has 27 host bits, giving 134,217,728 total addresses and 134,217,726 usable hosts.
/5 at a glance
| Property | Value |
|---|---|
| CIDR prefix | /5 |
| Subnet mask | 248.0.0.0 |
| Wildcard mask | 7.255.255.255 |
| Total addresses | 134,217,728 |
| Usable hosts | 134,217,726 |
| Host bits | 27 |
How it is calculated
A /5 sets the first 5 bits to 1 (network) and the remaining 27 bits to 0 (host). Usable hosts = 227 − 2 = 134,217,726.
The wildcard mask 7.255.255.255 is the inverse — used in Cisco ACLs and OSPF network statements.
Frequently asked questions
What is a /5 subnet mask?
A /5 equals 248.0.0.0 in dotted decimal (wildcard 7.255.255.255). It provides 134,217,728 total addresses and 134,217,726 usable hosts.
How many hosts are in a /5?
A /5 has 27 host bits, so it supports 134,217,726 usable hosts.
What is the wildcard mask for /5?
The wildcard (inverse) mask for /5 is 7.255.255.255, used in Cisco ACLs and OSPF statements.
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