A subnet mask of 255.255.255.224 is equivalent to which CIDR notation?

The subnet mask of 255.255.255.224 corresponds to a CIDR notation of /27. To understand this, it's essential to look at how subnet masks and CIDR notation relate to each other.

A subnet mask is a 32-bit number that masks an IP address and divides it into network and host portions. In the case of 255.255.255.224, the binary representation is:

• 255 → 11111111

• 255 → 11111111

• 255 → 11111111

• 224 → 11100000

When you count the number of 1s in the subnet mask's binary form, it totals 27. This means that the first 27 bits are used for the network part of the address, while the remaining 5 bits are available for host addresses within that subnet.

This configuration allows for 2^5 (or 32) possible addresses within the subnet, accounting for the network address and broadcast address, which leaves 30 usable host addresses.

Understanding this conversion is critical when subnetting a network, as CIDR notation provides a more concise way to represent subnet information. Hence, the correct CIDR notation for the subnet mask 255