Subnetting Questions 25 | Find the CIDR Value from the subnet mask

Subnetting Questions 25

What is the shorthand corresponding to a subnet mask of 255.255.255.128

or

Find the CIDR Value from the subnet mask 255.255.255.128

Solution

11111111 . 11111111 . 11111111 . 10000000

(2⁷ + 2⁶ + 2⁵ + 2⁴ + 2³ + 2² + 2¹ + 2⁰) . (2⁷ + 2⁶ + 2⁵ + 2⁴ + 2³ + 2² + 2¹ + 2⁰) . (2⁷ + 2⁶ + 2⁵ + 2⁴ + 2³ + 2² + 2¹ + 2⁰) . (2⁷)

255.255.255.128

Hence, there is 25 Network bits. So the CIDR Value from the subnet mask 255.255.255.128 is /25.