Objective

By the end of this lesson, students will understand the basics of how the internet resolves domain names to IP addresses, using tools like nslookup and curl. They will learn what CNAME records are and how to use these tools to explore the internet more effectively.

Materials and Prep

• A computer with internet access
• Access to a command line interface (Terminal on macOS/Linux, Command Prompt on Windows)
• A notebook and pen for taking notes

Before the lesson, make sure the student knows how to open the command line interface on their computer. It’s important to familiarize them with the basic commands.

Activities

• Activity 1: Exploring Domain Names

  Students will start by learning what a domain name is and how it relates to an IP address. They will use the nslookup command to find the IP address of a familiar website, like google.com, and write it down in their notebook.

• Activity 2: Understanding CNAME Records

  Next, students will learn about CNAME records. They will use the command `nslookup -q=cname` followed by a domain name to find CNAME records. Encourage them to choose different websites and see if they can find any CNAME records.

• Activity 3: Using Curl to Fetch Web Pages

  Students will then use the curl command to fetch the HTML content of a webpage. They can try `curl` followed by a website URL and see the raw HTML. Discuss what they see and how it relates to the websites they visit.

• Activity 4: Creative Web Exploration

  Finally, let students create a small project where they choose a website, find its CNAME records, and use curl to explore its content. They can present their findings to you or create a simple report.

Talking Points

• "What is a domain name? It's like the address of a house, but for a website!"
• "When you type a web address, your computer needs to find out where that website is located. That's where nslookup comes in!"
• "A CNAME record is like a nickname for a website. It tells your computer where to go when you type in a different name!"
• "Curl is a tool that helps you see the actual content of a website. It’s like looking behind the curtain!"
• "Why do you think knowing about these tools is useful? It helps you understand how the internet works and can make you a better internet explorer!"