Class C address subnetting
/25
The subnet mask is 128;
A value of 1, the other seven bits ranging from 0 (10000000);
Block size 128; (256-128);
Two subnets, each containing up to 126 hosts;
/26
Subnet mask 192
2 is a value of the other six values 0 (110,000,000);
Block size of 64; (256-192);
4 subnets, each containing a maximum of 62 hosts
/27
Subnet mask 224
3 is a value of 1, the other five values is 0 (11,100,000);
32 block size; (256-224);
8 subnets, each containing up to 30 hosts
/28
Subnet mask 240
4 is a value of 1, the other 4 as the value of 0 (11110000);
Block size is 16 (256-240);
16 subnets, each containing up to 14 hosts
/29
Subnet mask 248
5 The value is 1, the other three values 0 (11111000);
Block size is 8 (256-248);
32 subnets, each containing up to 6 hosts
/30
Subnet mask 252
Value of 6 to 1, the other two values 0 (11111100);
Block size is 4 (256-252);
64 subnets, each containing up to 2 hosts