For enhanced IP address management, Classless Inter-Domain Routing (CIDR) was introduced to facilitate the use of subnetworks such as /26, /27, etc., instead of solely relying on classful IP addresses like Class A, Class B, and Class C. This post provides a concise overview of the /26 subnet mask.
/26 Subnet Meaning
A /26 subnet mask represents a network prefix length with 26 network bits and 6 host bits in binary notation. When applied, a /26 subnet mask divides a network into 64 IP ranges. The first IP address within this range serves as the network address, while the last IP is designated as the broadcast IP. Hence, within the /26 subnet mask, there are 62 usable IP addresses available for devices and hosts.
/26 Subnet Mask Usable IP Address
Within a /26 subnet mask, there are 62 usable IP addresses. Although there are 64 IP addresses in total, the first is reserved for the network address, and the last is reserved for the broadcast address.
For instance, let’s consider subnetting the network 192.168.2.0/24 with a /26 subnet mask. The first subnet will consist of the network address 192.168.2.0, a usable IP range from 192.168.2.1 to 192.168.2.62, and the broadcast address of 192.168.2.63. The second subnet will have a network address of 192.168.2.64, a usable IP range of 192.168.2.65 to 192.168.2.126 and a broadcast address of 192.168.2.127, and so on (till the fourth subnet).
| Network Address | Usable IP address | Broadcast IP address |
|---|---|---|
| .0 | .1-.62 | .63 |
| .64 | .65-.126 | .127 |
| .128 | .129-.190 | .191 |
| .192 | .193-.254 | .255 |
/26 Subnet Mask Dotted Decimal Notation
The dotted decimal notation for a /26 subnet mask is 255.255.255.192. This representation is gotten by setting the first 26 bits of the 32-bit IPv4 address to ‘1s’, setting the remaining 6 bits to ‘0s’, and converting from binary to decimals.
Subnetting Class C Network with /26 Subnet Mask
When subnetting a Class C network with a /26 subnet mask, 2 bits are borrowed for subnetting, leaving 6 bits for host addresses within each subnet.
Hence, the number of subnet obtainable when subnetting class C network with /26 is gotten as follow.
2^2 = 4
Thus, subnetting a Class C network with a /26 prefix length divides the Class C network into 4 subnetworks, each having 64 IP range including network address and the broadcast address.
Subnetting Class B Network with /26 Subnet Mask
Subnetting a Class B network with a /26 subnet mask involves borrowing 10 bits for subnetting, leaving 6 bits for host addresses within each subnet.
Hence, the number of subnet obtainable when subnetting class B network with /26 is gotten as follow.
2^10 = 1024
So, a /26 subnet will divide a Class B network into 1024 subnetworks. Each subnetwork will have 62 usable IP addresses and 64 IP range.
Subnetting Class A Network with /26 Subnet Mask
When subnetting a Class A network with a /26 subnet mask, 18 bits are borrowed for subnetting, leaving 6 bits for host addresses within each subnet.
So, the number of host per subnet is gotten as follow;
2^18 = 262144
This means that a /26 subnet will divide a Class A network into 262,144 subnetworks. Each subnetwork will have its own 64 usable IP addresses.
Conclusion
/26 subnet mask generally provides 64 IP address per a subnetwork. Then number of Subnetwork obtainable when we subnet with /26 subnet mask depends on the Class of the network. As we have shown above, class C network will yield 4 subnetwork, Class B network will yield 1024 subnetwork and Class A network will yield 262144 subnetwork when subnetted with /26 prefix length
I am a passionate Networking Associate specializing in Telecommunications.
With a degree in Electronic engineering, I possess a strong understanding of electronic systems and the intricacies of telecommunications networks. I gained practical experience and valuable insights working for a prominent telecommunications company.
Additionally, I hold certifications in networking, which have solidified my expertise in network architecture, protocols, and optimization.
Through my writing skills, I aim to provide accurate and valuable knowledge in the networking field.
Connect with me on social media using the links below for more insights.
You can contact me using [email protected] or connect with me using any of the social media account linked below