/26 Subnet Mask: 255.255.255.192
A /26 IPv4 subnet uses mask 255.255.255.192. It provides 64 total addresses and 62 traditional usable host addresses. The fourth-octet block size is 64 and its wildcard mask is 0.0.0.63.
/26 quick reference
| Prefix and binary | /26 · 11111111.11111111.11111111.11000000 |
|---|---|
| Subnet mask | 255.255.255.192 |
| Wildcard mask | 0.0.0.63 |
| Total / usable | 64 total · 62 traditional usable |
| Increment | 64 in the fourth octet |
Worked example: 192.168.10.0/26
Six host bits remain, so 2^6 = 64 addresses fit in the subnet. For the first /26 of 192.168.10.0/24:
| Network | First host | Last host | Broadcast |
|---|---|---|---|
| 192.168.10.0 | 192.168.10.1 | 192.168.10.62 | 192.168.10.63 |
The next subnet begins at 192.168.10.64/26. This boundary check is a fast way to catch the common mistake of assigning .63 to a device.
The four /26 networks inside a /24
| Network | Usable hosts | Broadcast |
|---|---|---|
| 192.168.10.0/26 | .1–.62 | .63 |
| 192.168.10.64/26 | .65–.126 | .127 |
| 192.168.10.128/26 | .129–.190 | .191 |
| 192.168.10.192/26 | .193–.254 | .255 |
This layout is useful when a /24 allocation must be divided among four departments or VLANs of up to 62 addressed devices each. Include gateways, printers, access points, management interfaces and growth in the count; “50 users” rarely means only 50 IP addresses.
Wildcard-mask example and design caution
The wildcard for /26 is 0.0.0.63. A Cisco ACL line such as access-list 20 permit 192.168.10.64 0.0.0.63 matches the second /26. In OSPF or ACL configuration, confirm the command’s meaning on that platform; wildcard syntax identifies an address set but does not validate the security or routing intent.
A /26 is not automatically “best” for 62 devices. If the segment is expected to grow, choose headroom or redesign the VLAN plan before addresses run out. If only a handful of devices exist, a smaller prefix may conserve space.
Frequently asked questions
What is the subnet mask for /26?
The /26 subnet mask is 255.255.255.192.
How many usable hosts does /26 support?
A /26 contains 64 total IPv4 addresses and 62 traditional usable host addresses.
What is the wildcard mask for /26?
The /26 wildcard mask is 0.0.0.63.
What are the /26 subnet boundaries in a /24?
They begin at fourth-octet values 0, 64, 128 and 192.
Primary sources
- RFC 1878: Variable Length Subnet Table for IPv4
- Cisco: understand host and subnet quantities
- Cisco IOS: wildcard masks in access lists
Port registrations describe assigned names, not a guarantee about the process actually listening on a device. Confirm the local process and configuration before changing a firewall.
Related guides
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