Subnetting: 10-Question Practice Exam

Subnetting is a foundational skill that you'll find on the CCENT, CCNA, and even the Network+. Unlike the other five practice exams in this Gut Check Assessment series, subnetting isn't going away. Nine Cisco exams may be retiring, but subnetting is here to stay.

Try these 10 subnetting questions after you watch Keith Barker's subnetting training to see how you're doing with one of the most important skills you'll learn.

1. The process of subnetting refers to what?

1. Stealing bits from the network portion of the address to create more sub networks

2. Stealing bits from the subnet mask in order to create more sub networks

3. Stealing bits from the host portion of the address to create more sub networks

4. Stealing bits from the inverse mask in order to create more sub networks

Explanation: Subnetting is stealing bits from the host portion of the IP address in order to create more sub networks.

2. What is the correct binary representation of 41?

1. 00010011

2. 01101101

3. 10010001

4. 00101001

Explanation: 00101001 is 41 in decimal. Notice the values of 32, 8, and 1 are (on) in the binary.

3. What is the purpose of a subnet mask in an IP address and mask combination?

1. To indicate the default gateway IP address

2. To dictate the physical location of the address

3. To save on the possible addresses that you can use in the network

4. To delineate the network portion of the address from the host portion

Explanation: The subnet mask depicts the portion of the IP address that indicates the network from the portion of the address that indicates the host address on the network.

4. Which of the following statements about VLSM is incorrect?

1. It is not possible to use a /31 bit mask in production

2. When you use VLSM, you are taking an unused subnet and further subnetting it

3. You can create subnets of just the right size with VLSM

4. VLSM helps with summarization in networks

Explanation: Many routers in production can use a /31 mask. This is often done on WAN links where no more than two nodes are addressed in the subnet.

5. What command would you use on a Windows system to find your IP address at the command line?

1. ifconfig

2. ipconfig

3. intconfig

4. addconfig

Explanation: Use the ipconfig command at a command prompt to discover you IP address on a Window system.

6. How many bits are in one of the four octets of an IP address?

1. 4

2. 8

3. 16

4. 32

Explanation: There are 8 bits in an octet of an IP address. An IP address is made up of 4 of these octets. There is a total of 32 bits in an IP address.

7. What is often considered the "ultimate" aggregate route in a v4 network?

1. A default route

2. A static route

3. A default gateway host route

4. Any host route

Explanation: A default route 0.0.0.0/0 summarizes the entire v4 address space.

8. What is the default subnet mask for a Class B address?

1. 255.0.0.0

2. 255.255.0.0

3. 255.255.255.0

4. 255.255.255.255

Explanation: A Class B address defaults to the network portion as the first two octets. This means the default subnet mask is 255.255.0.0.

9. You are using a subnet mask subnetting scheme that contains 28 bits. How many host bits are there for host addressing?

1. 3

2. 4

3. 5

4. 6

Explanation: Since an address is 32 bits, and you are using 28 bits in the subnet mask to identify the network portion, this leaves 4 bits for host addressing.

10. The broadcast address of a subnet is the next subnet address minus what?

1. 1

2. 2

3. 3

4. 4

Correct Answer: a

Explanation: The broadcast address for a subnet is the address of the next network, minus 1.