This is the below table you have to memories for understanding the subnetting trick.





Question: We have IP address: 192.168.10.1/24 Please find the below parameter.





Solution:









Step 1. In the bottom line (Number of Valid Subnets), move from right to left and find the closest number that is bigger than or equal to what you need:

Default mask for Class C: 255.255.255.0