IP addresses and domain names in Intro to Computing - Draw & Build Visually

Draw This - beginner

Draw a diagram that shows how a domain name like www.example.com is translated into an IP address such as 192.168.1.1. Include the steps of typing the domain name, the DNS lookup process, and the final IP address resolution.

10 minutes

Hint 1

Hint 2

Hint 3

Hint 4

Grading Criteria

Diagram shows user typing domain name

DNS server is shown as a separate entity

Arrow from user to DNS server labeled as DNS request

Arrow from DNS server to user labeled as DNS response with IP address

Final connection from user/browser to web server using IP address

Clear labels for domain name and IP address

Start and end points are clearly indicated

Solution

  +----------------+        +----------------+        +----------------+
  | User types     |        | DNS Server     |        | Web Server     |
  | www.example.com| -----> | Looks up IP    | -----> | IP: 192.168.1.1|
  +----------------+        +----------------+        +----------------+
          |                         ^                         |
          |                         |                         |
          |-------------------------|-------------------------|
                     DNS lookup request and response

1. The user types the domain name www.example.com into their web browser.

2. The browser sends a request to a DNS (Domain Name System) server to find the IP address linked to that domain name.

3. The DNS server looks up its records and finds the IP address 192.168.1.1 associated with www.example.com.

4. The DNS server sends the IP address back to the browser.

5. The browser uses the IP address to connect to the web server and load the website.

This process is like looking up a phone number in a phone book when you know the person's name.

Variations - 2 Challenges

[intermediate] Draw a flowchart showing the steps a computer takes to resolve a domain name to an IP address, including checking local cache before querying the DNS server.

[advanced] Draw a detailed diagram showing how multiple DNS servers (recursive and authoritative) work together to resolve the domain name www.example.com to its IP address.

Practice

1. What is the main purpose of a domain name in internet communication?

easy

A. To assign a unique numeric label to a device

B. To provide an easy-to-remember name linked to an IP address

C. To encrypt data sent over the internet

D. To store website content

Solution

1. Step 1: Understand what domain names represent

   Domain names are human-friendly names that help us remember website addresses instead of numbers.

2. Step 2: Compare domain names with IP addresses

   IP addresses are numeric labels, while domain names are easy names linked to those numbers.

3. Final Answer:

   To provide an easy-to-remember name linked to an IP address -> Option B

4. Quick Check:

   Domain name = Easy-to-remember name [OK]

Hint: Domain names are like website nicknames [OK]

Common Mistakes:

• Confusing domain names with IP addresses
• Thinking domain names encrypt data
• Believing domain names store website content

2. Which of the following is the correct format of an IPv4 address?

easy

A. 192.168.1.1

B. 192-168-1-1

C. 192:168:1:1

D. 192/168/1/1

Solution

1. Step 1: Recall IPv4 address format

   IPv4 addresses consist of four numbers separated by dots, each number between 0 and 255.

2. Step 2: Check each option's format

   Only 192.168.1.1 uses dots as separators and valid numeric ranges.

3. Final Answer:

   192.168.1.1 -> Option A

4. Quick Check:

   IPv4 uses dots between numbers [OK]

Hint: IPv4 addresses use dots, not dashes or colons [OK]

Common Mistakes:

• Using dashes or colons instead of dots
• Confusing IPv4 with IPv6 format
• Using slashes as separators

3. Given the domain name example.com, what does the DNS server do when you type it in your browser?

medium

A. It translates example.com into its IP address

B. It encrypts your browsing data

C. It stores the website files locally

D. It blocks access to the website

Solution

1. Step 1: Understand DNS server role

   DNS servers translate domain names into IP addresses so browsers can find websites.

2. Step 2: Match the action to the options

   Only It translates example.com into its IP address describes this translation process correctly.

3. Final Answer:

   It translates example.com into its IP address -> Option A

4. Quick Check:

   DNS = Domain to IP translation [OK]

Hint: DNS converts names to numbers (IP addresses) [OK]

Common Mistakes:

• Thinking DNS encrypts data
• Believing DNS stores website files
• Assuming DNS blocks websites

4. A user tries to access www.example.com but gets an error. The DNS server is suspected. Which of these is a likely cause?

medium

A. The website files are missing on the server

B. The user's computer has no internet cable connected

C. The browser cache is full

D. The DNS server failed to translate the domain name to an IP address

Solution

1. Step 1: Identify DNS server's role in domain resolution

   If DNS fails, the domain name cannot be converted to an IP address, causing access errors.

2. Step 2: Evaluate other options

   Options A, B, and D relate to other issues, not DNS translation failure.

3. Final Answer:

   The DNS server failed to translate the domain name to an IP address -> Option D

4. Quick Check:

   DNS failure = domain name not resolved [OK]

Hint: DNS failure means no IP address found for domain [OK]

Common Mistakes:

• Confusing DNS failure with physical connection issues
• Blaming browser cache for DNS errors
• Assuming website files missing cause DNS errors

5. You want to block access to a website by modifying the local hosts file. Which entry correctly blocks badwebsite.com by redirecting it to the local machine?

hard

A. 255.255.255.0 badwebsite.com

B. 192.168.1.1 badwebsite.com

C. 127.0.0.1 badwebsite.com

D. 0.0.0.0 badwebsite.com

Solution

1. Step 1: Understand hosts file redirection

   The hosts file maps domain names to IP addresses locally. Redirecting to 127.0.0.1 (localhost) blocks the site.

2. Step 2: Evaluate IP addresses for blocking

   127.0.0.1 is the standard localhost IP; 192.168.1.1 is a private network IP; 255.255.255.0 is a subnet mask; 0.0.0.0 can also block but 127.0.0.1 is more common and reliable.

3. Final Answer:

   127.0.0.1 badwebsite.com -> Option C

4. Quick Check:

   Hosts file redirect to localhost = block site [OK]

Hint: Use 127.0.0.1 to block sites via hosts file [OK]

Common Mistakes:

• Using subnet masks or invalid IPs in hosts file
• Confusing private IPs with localhost
• Using 0.0.0.0 which may not work on all systems