CCST IP Addressing & Subnetting — Questions and Answers

Question 1: What is a valid IPv4 address?

192.168.1.1 (Correct answer)
300.1.1.1
10.0.0.256
192.168.1.999

Correct answer: 192.168.1.1

A valid IPv4 address consists of four octets (numbers) separated by dots, where each octet must be an integer between 0 and 255, inclusive. Options B, C, and D contain numbers (300, 256, 999) that fall outside this permissible range, making them invalid. The address 192.168.1.1 correctly adheres to these rules, as all its octets are within the 0-255 range.

Question 2: What is the subnet mask for a Class C network?

255.0.0.0
255.255.0.0
255.255.255.0 (Correct answer)
255.255.255.255

Correct answer: 255.255.255.0

In traditional Class C networking, the first three octets of an IP address identify the network, while the last octet identifies the host within that network. A subnet mask of 255.255.255.0 reflects this structure by having '255' in the first three octets (designating the network portion) and '0' in the last octet (designating the host portion). This mask allows for 254 usable host IP addresses in a Class C network.

Question 3: What is CIDR notation?

/24 (Correct answer)
255.255.255.0
/8
/32

Correct answer: /24

CIDR (Classless Inter-Domain Routing) notation is a concise method for representing an IP address and its associated network mask. It appends a forward slash followed by a number to the IP address, where this number indicates the count of contiguous '1' bits in the subnet mask. For instance, /24 signifies that the first 24 bits of the IP address define the network portion, which corresponds to a subnet mask of 255.255.255.0.

Question 4: How many hosts can a /29 subnet support?

8
6 (Correct answer)
2
14

Correct answer: 6

A /29 subnet mask indicates that 29 bits are used for the network portion, leaving 3 bits for the host portion (32 total bits - 29 network bits = 3 host bits). This allows for 2^3 = 8 total IP addresses in the subnet. However, two addresses are reserved: one for the network ID and one for the broadcast address. Therefore, the number of usable host addresses is 8 - 2 = 6.

Question 5: Which address is reserved for broadcasts?

First IP
Last IP in subnet (Correct answer)
Subnet mask
Gateway

Correct answer: Last IP in subnet

Within any given IP subnet, the very last IP address is always reserved for the broadcast address. This special address is used to send data simultaneously to all devices connected within that specific subnet. Conversely, the first IP address in a subnet is reserved for the network address itself.

Question 6: What is a private IP range?

8.8.8.8
172.32.0.0
192.168.0.0/16 (Correct answer)
1.1.1.1

Correct answer: 192.168.0.0/16

Private IP address ranges are specifically designated for use within private networks (such as home or office networks) and are not routable on the public internet. RFC 1918 defines three primary private ranges: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Option C, 192.168.0.0/16, falls directly within one of these standardized private address blocks.

Question 7: What does subnetting do?

Connects devices
Assigns MACs
Divide large network (Correct answer)
Converts DNS

Correct answer: Divide large network

Subnetting is the process of dividing a single large IP network into multiple smaller, more manageable subnetworks. This practice offers several benefits, including improved network efficiency by reducing broadcast traffic, enhanced security through network segmentation, and more efficient allocation of IP addresses. It is a fundamental technique for organizing and optimizing network resources.

Question 8: What tool helps calculate subnets?

Ping
Traceroute
Subnet calculator (Correct answer)
Telnet

Correct answer: Subnet calculator

A subnet calculator is a specialized tool designed to simplify the complex mathematical calculations involved in subnetting. It assists network administrators in quickly determining critical subnet parameters such as network addresses, broadcast addresses, valid host ranges, and the total number of available hosts for a given IP address and subnet mask or CIDR notation. While other network tools exist, a subnet calculator is specifically tailored for this purpose.

Question 9: What is the network address in 192.168.1.10/24?

192.168.1.1
192.168.1.10
192.168.1.255
192.168.1.0 (Correct answer)

Correct answer: 192.168.1.0

The network address is the first address in a given subnet and serves to identify the network itself. For the IP address 192.168.1.10 with a /24 CIDR notation, the /24 indicates that the first 24 bits (the first three octets) represent the network portion. To determine the network address, all host bits (the last 8 bits in this case) are set to zero, resulting in 192.168.1.0.

CCST IP Addressing & Subnetting

What is a valid IPv4 address?