Subnetting Questions 6 | Find the Subnet Mask from IP Address

Subnetting Question 6

You have a network ID of 192.168.10.0 and require at least 25 hosts for each subnet, with the largest amount of subnets available. Which subnet mask should you assign?

Solution

Hence, 192.168.10.0 is a class C IP Address and by default, its network bit is 24 and host bit is 8.

A/Q, we need a minimum of 25 hosts with maximum subnets.

So, we have to reserve 5 bits for the host from the last octet (2⁵ = 32). This is the number of host closest to 25 and the remaining 3 bits are the network bits.

(11111111.11111111.11111111.11100000)

(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 + 2⁶ + 2⁵ )

So, the subnet mask is 255.255.255.224

Here is a video tutorial of this subnetting question.