Computer Science · Grade 10 · Networks and the Internet · Term 2

IP Addresses and DNS

Understand how devices are identified on a network using IP addresses and how the Domain Name System (DNS) translates human-readable names.

• Ontario Curriculum Expectations
• CS.HS.N.3
• CS.HS.N.4

About This Topic

IP addresses act as unique numerical labels for devices on a network, ensuring data packets reach the correct destination. Grade 10 students differentiate between IPv4 addresses, like 192.168.1.1, and longer IPv6 formats, while distinguishing public IPs exposed to the internet from private ones used locally. They also examine the Domain Name System (DNS), which converts human-readable domain names, such as ontario.ca, into these IP addresses via a multi-step resolution process.

Positioned in the Networks and the Internet unit, this topic builds foundational knowledge of internet infrastructure. Students explain DNS queries that start at the client, move to recursive resolvers, then cascade through root, TLD, and authoritative servers. They analyze how unique identifiers prevent collisions, support scalable routing, and underpin protocols like TCP/IP, preparing for advanced studies in cybersecurity and data integrity.

Active learning excels with this topic because networking concepts feel distant until students interact directly. Tracing real DNS lookups on their devices or simulating packet paths in groups makes resolution steps visible and memorable, helping students articulate processes confidently during discussions.

Key Questions

1. Differentiate between an IP address and a domain name.
2. Explain the process of DNS resolution when accessing a website.
3. Analyze the importance of unique identifiers for devices on a network.

Learning Objectives

• Compare the structure and function of IPv4 and IPv6 addresses.
• Explain the hierarchical process of DNS resolution from client to authoritative server.
• Analyze the necessity of unique network identifiers for seamless data transmission and network scalability.
• Differentiate between public and private IP addresses and their respective use cases.

Before You Start

Introduction to Computer Networks

Why: Students need a basic understanding of what a network is and how devices communicate to grasp the function of IP addresses and DNS.

Data Transmission Basics

Why: Understanding how data is broken into packets and sent across networks provides context for why unique identifiers are necessary.

Key Vocabulary

IP Address	A unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It serves as a network address for identification and location addressing.
Domain Name System (DNS)	A hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network. It translates human-readable domain names into machine-readable IP addresses.
DNS Resolution	The process by which a DNS client queries DNS servers to obtain the IP address associated with a specific domain name. This involves a series of requests to different types of DNS servers.
IPv4	The fourth version of the Internet Protocol, which uses a 32-bit address scheme to provide a unique numerical address for each device on a network. It is the most common IP addressing standard currently in use.
IPv6	The latest version of the Internet Protocol, designed to replace IPv4. It uses a 128-bit address scheme, providing a vastly larger pool of unique IP addresses to accommodate the growing number of internet-connected devices.
Public IP Address	An IP address that is assigned directly to a device and is routable on the global Internet. These addresses are unique across the entire internet.
Private IP Address	An IP address from a special range reserved for use within private networks, such as home or office networks. These addresses are not routable on the global Internet and are translated to a public IP address by a router.

Watch Out for These Misconceptions

Common Misconception

IP addresses are permanent and never change for a device.

What to Teach Instead

Most IPs are dynamic, assigned temporarily by DHCP servers to manage limited address space. Hands-on checks of a device's IP before and after a network restart reveal changes, while pair discussions clarify static versus dynamic uses in real networks.

Common Misconception

DNS is a single central database holding all domain-IP mappings.

What to Teach Instead

DNS operates as a distributed hierarchy across global servers. Role-play simulations where students relay queries through 'servers' demonstrate the step-by-step process, correcting the idea of central storage and highlighting redundancy benefits.

Common Misconception

A domain name is just a friendly version of the IP address itself.

What to Teach Instead

Domain names are symbolic labels resolved to IPs via DNS protocols. Tracing live lookups in small groups shows the translation gap, helping students grasp why names persist even if IPs shift behind them.

Active Learning Ideas

Terminal Task: DNS Resolution Trace

Pairs open command line tools like nslookup or dig. They enter domain names such as google.com and bbc.co.uk, record the IP addresses returned and query steps shown. Groups then compare results and diagram the resolution path on chart paper.

30 min·Pairs

Network Scan: Classroom IP Hunt

Small groups install safe tools like Advanced IP Scanner. They scan the local Wi-Fi network to list device IPs and hostnames. Teams categorize public versus private addresses and discuss uniqueness needs.

45 min·Small Groups

Simulation Game: DNS Query Relay

Assign roles as client, resolver, root server, TLD server, and authoritative server. The client calls out a domain; servers relay queries step-by-step around the room. Switch roles twice and debrief on failure points.

40 min·Whole Class

Debug Drill: IP Conflict Scenarios

Individuals read case studies of duplicate IPs causing network issues. They propose fixes like DHCP reservations, then test by pinging conflicting addresses on a simulated LAN using virtual machines if available.

35 min·Individual

Real-World Connections

• Web hosting companies like GoDaddy and Namecheap manage millions of domain names and their corresponding IP addresses, ensuring that when you type a website address into your browser, you are directed to the correct server.
• Internet Service Providers (ISPs) like Rogers or Bell assign public IP addresses to your home router, enabling your entire network to connect to the internet. They also manage DNS servers that translate website names for their customers.
• Cybersecurity professionals analyze network traffic logs, which include IP addresses, to detect malicious activity, identify the source of attacks, and trace the path of data breaches.

Assessment Ideas

Exit Ticket

Provide students with a scenario: 'You type www.google.com into your browser.' Ask them to list, in order, the three main types of DNS servers involved in resolving this request and briefly state the role of each. Also, ask them to identify if the IP address for google.com is likely public or private.

Quick Check

Display two IP addresses on the board, one IPv4 (e.g., 172.16.254.1) and one IPv6 (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). Ask students to write down which is which and one key difference between the two formats.

Discussion Prompt

Pose the question: 'Imagine a large school network with hundreds of computers. Why is it essential for each computer to have a unique identifier, and what problems could arise if two computers accidentally had the same IP address?' Facilitate a class discussion on network collisions and data routing.

Frequently Asked Questions

What is the difference between an IP address and a domain name?

An IP address is a numerical identifier, such as 192.0.2.1 for IPv4 or 2001:db8::1 for IPv6, used by routers to locate devices. A domain name, like example.com, is a memorable text label. DNS servers translate domains to IPs during web access, making the internet user-friendly while preserving precise routing.

How does the DNS resolution process work?

Resolution begins when a device queries its configured DNS resolver with a domain name. The resolver checks its cache; if no match, it queries root servers for TLD guidance, then TLD servers for authoritative nameservers, and finally gets the IP. Caching speeds future lookups, ensuring efficient global access.

Why are unique IP addresses essential for networks?

Unique IPs prevent data packets from reaching wrong devices, avoiding collisions and ensuring reliable communication. In large networks like the internet, protocols like ARP map IPs to MAC addresses for local delivery. Duplicates cause outages; IPv6 expansion addresses exhaustion of IPv4 space for continued growth.

How can active learning help students grasp IP addresses and DNS?

Active approaches like command-line DNS traces and network scans let students see real IPs and resolution in action on their devices. Simulations with role relays clarify abstract hierarchies, while group mapping of classroom networks reinforces uniqueness. These methods turn passive recall into confident troubleshooting skills through direct experimentation and peer explanation.