/26 subnet (255.255.255.192)

A /26 network has 64 addresses, of which 62 can be given to hosts after the network and broadcast addresses. Part of a /24, used to split one class C-sized network into smaller segments.

CIDR notation
/26
Subnet mask
255.255.255.192
Wildcard mask
0.0.0.63
Binary mask
11111111.11111111.11111111.11000000
Total addresses
64
Usable hosts
62
Example network
192.168.1.0/26
Example usable range
192.168.1.1 – 192.168.1.62
/26 networks in a /24
4

Calculate a /26 for your own address

192.168.1.0/24 split into /26 networks

NetworkUsable rangeBroadcast
192.168.1.0/26192.168.1.1 – 192.168.1.62192.168.1.63
192.168.1.64/26192.168.1.65 – 192.168.1.126192.168.1.127
192.168.1.128/26192.168.1.129 – 192.168.1.190192.168.1.191
192.168.1.192/26192.168.1.193 – 192.168.1.254192.168.1.255

In firewall rules and investigations

A /26 rule matches every address from 192.168.1.0 to 192.168.1.63. In Cisco ACLs the same range is written with the wildcard mask 0.0.0.63. When an alert names an IP, checking whether it falls inside a known /26 (your own network, a cloud provider’s published range or a blocked range) is often the quickest first step.