/6 Subnet Mask
A /6 prefix means the subnet mask is 252.0.0.0. It has 26 host bits, giving 67,108,864 total addresses and 67,108,862 usable hosts.
/6 at a glance
| Property | Value |
|---|---|
| CIDR prefix | /6 |
| Subnet mask | 252.0.0.0 |
| Wildcard mask | 3.255.255.255 |
| Total addresses | 67,108,864 |
| Usable hosts | 67,108,862 |
| Host bits | 26 |
How it is calculated
A /6 sets the first 6 bits to 1 (network) and the remaining 26 bits to 0 (host). Usable hosts = 226 − 2 = 67,108,862.
The wildcard mask 3.255.255.255 is the inverse — used in Cisco ACLs and OSPF network statements.
Frequently asked questions
What is a /6 subnet mask?
A /6 equals 252.0.0.0 in dotted decimal (wildcard 3.255.255.255). It provides 67,108,864 total addresses and 67,108,862 usable hosts.
How many hosts are in a /6?
A /6 has 26 host bits, so it supports 67,108,862 usable hosts.
What is the wildcard mask for /6?
The wildcard (inverse) mask for /6 is 3.255.255.255, used in Cisco ACLs and OSPF statements.
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