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Intro to Computingfundamentals~10 mins

IP addresses and domain names in Intro to Computing - Interactive Code Practice

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Practice - 5 Tasks
Answer the questions below
1fill in blank
easy

Complete the code to print the IP address of a website using Python's socket module.

Intro to Computing
import socket
ip = socket.gethostbyname([1])
print(ip)
Drag options to blanks, or click blank then click option'
Alocalhost
Bexample.com
C"localhost"
D"example.com"
Attempts:
3 left
💡 Hint
Common Mistakes
Forgetting to put quotes around the domain name string.
Using a variable name without defining it.
2fill in blank
medium

Complete the code to split an IP address string into its four parts.

Intro to Computing
ip = "192.168.1.1"
parts = ip.[1](".")
print(parts)
Drag options to blanks, or click blank then click option'
Asplit
Breplace
Cjoin
Dfind
Attempts:
3 left
💡 Hint
Common Mistakes
Using join which combines strings instead of splitting.
Using replace which changes characters but does not split.
3fill in blank
hard

Fix the error in the code that checks if an IP address is valid by counting its parts.

Intro to Computing
ip = "10.0.0.256"
parts = ip.split(".")
if len(parts) [1] 4:
    print("Valid IP")
else:
    print("Invalid IP")
Drag options to blanks, or click blank then click option'
A==
B!=
C=
D<
Attempts:
3 left
💡 Hint
Common Mistakes
Using = instead of == causes syntax errors.
Using != reverses the logic.
4fill in blank
hard

Fill both blanks to create a dictionary mapping domain names to their IP addresses.

Intro to Computing
import socket

domains = ["example.com", "localhost"]
ip_map = {domain: [1] for domain in domains if domain [2] "localhost"}
print(ip_map)
Drag options to blanks, or click blank then click option'
Asocket.gethostbyname(domain)
B==
C!=
Ddomain
Attempts:
3 left
💡 Hint
Common Mistakes
Using == instead of != changes the filter logic.
Not calling the function to get IP addresses.
5fill in blank
hard

Fill all three blanks to create a list of IP addresses from a list of domain names.

Intro to Computing
import socket

domains = ["example.com", "localhost", "openai.com"]
ips = [[1] for [2] in domains if [3] != "localhost"]
print(ips)
Drag options to blanks, or click blank then click option'
Asocket.gethostbyname(domain)
Bdomain
Dsocket.gethostbyname(dom)
Attempts:
3 left
💡 Hint
Common Mistakes
Using different variable names inconsistently.
Calling the function with wrong variable names.

Practice

(1/5)
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