Palo Alto Networks (PANW) Certified Cybersecurity Entry-level Technician (PCCET) Practice Exam

How many /28 subnets can you fit in a class C?

1. 2

2. 4

3. 8

4. 16

The correct answer is: 16

To understand how many /28 subnets can fit into a Class C subnet, it's important to first recognize the structure of Class C and how subnetting works. A Class C IP address has a default subnet mask of 255.255.255.0, which corresponds to a /24 prefix. This means there are 256 total addresses in a Class C network (from 0 to 255 in the last octet). When you create /28 subnets, you are using the first 28 bits for the network portion and leaving 4 bits for the host portion because a full IPv4 address is 32 bits. In a /28 subnet, the subnet mask is 255.255.255.240. This allows for 16 addresses per /28 subnet (2^4 = 16). However, out of these 16 addresses, 2 addresses are reserved: one for the network address and one for the broadcast address. This means each /28 subnet can accommodate 14 usable IP addresses. To determine how many /28 subnets fit into a Class C network with a /24 prefix, consider the number of addresses available in each level of subnetting. Since a /24 has 256 addresses and each /28 uses