What is the CIDR notation for a subnet mask of 255.255.255.128?
Practice Questions
Q1
What is the CIDR notation for a subnet mask of 255.255.255.128?
/25
/26
/27
/24
Questions & Step-by-Step Solutions
What is the CIDR notation for a subnet mask of 255.255.255.128?
Step 1: Understand what a subnet mask is. A subnet mask helps to divide an IP address into a network part and a host part.
Step 2: Convert the subnet mask 255.255.255.128 into binary. This is done by converting each octet (number between the dots) into an 8-bit binary number.
Step 3: The binary representation of 255.255.255.128 is: 11111111.11111111.11111111.10000000.
Step 4: Count the number of '1's in the binary representation. Each '1' represents a bit used for the network.
Step 5: In the binary representation, there are 25 '1's before the first '0'.
Step 6: The CIDR notation is written as a slash followed by the number of '1's counted. Therefore, it is /25.
