IP addresses (IPv4, IPv6) in Intro to Computing - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding IPv4 Address Structure

Which of the following best describes the structure of a standard IPv4 address?

A Four groups of decimal numbers separated by dots, each group ranging from 0 to 255

B Eight groups of hexadecimal numbers separated by colons, each group ranging from 0 to FFFF

C A single 32-bit binary number without any separators

D Four groups of decimal numbers separated by commas, each group ranging from 0 to 999

💡 Hint

Think about how IPv4 addresses are commonly written in everyday use.

IPv4 addresses are written as four decimal numbers separated by dots. Each number can be from 0 to 255 because each group represents 8 bits (1 byte).

❓ trace

intermediate

Converting IPv4 to Binary

What is the binary representation of the IPv4 address 192.168.1.1?

A 11000000.10101000.00000001.00000001

B 11000000.10101000.00000010.00000001

C 11000001.10101000.00000001.00000001

D 11000000.10101001.00000001.00000001

💡 Hint

Convert each decimal number to an 8-bit binary number.

192 in binary is 11000000, 168 is 10101000, 1 is 00000001. So the full address is 11000000.10101000.00000001.00000001.

❓ identification

advanced

Identifying Valid IPv6 Address Format

Which of the following is a valid IPv6 address?

A 192.168.1.1

B 2001:0db8:85a3:0000:0000:8a2e:0370:7334

C 2001.0db8.85a3.0000.0000.8a2e.0370.7334

D 2001:0db8:85a3:0000:0000:8a2e:0370:7334:12345

💡 Hint

IPv6 addresses use colons and hexadecimal groups.

Option B is a valid IPv6 address with eight groups of four hexadecimal digits separated by colons. Option B is IPv4. Option B uses dots incorrectly. Option B has a group with too many digits.

❓ Comparison

advanced

Comparing IPv4 and IPv6 Address Lengths

Which statement correctly compares the length of IPv4 and IPv6 addresses?

A IPv4 addresses are 128 bits long; IPv6 addresses are 32 bits long

B IPv4 addresses are 16 bits long; IPv6 addresses are 64 bits long

C Both IPv4 and IPv6 addresses are 64 bits long

D IPv4 addresses are 32 bits long; IPv6 addresses are 128 bits long

💡 Hint

Recall the bit length of each IP version.

IPv4 uses 32 bits allowing about 4 billion addresses. IPv6 uses 128 bits, vastly increasing address space.

🚀 Application

expert

Calculating Number of Possible IPv6 Addresses

Given that an IPv6 address is 128 bits long, how many unique IPv6 addresses are possible?

A Approximately 2.1 x 10^12 addresses

B Approximately 1.6 x 10^19 addresses

C Approximately 3.4 x 10^38 addresses

D Approximately 4.3 x 10^9 addresses

💡 Hint

Calculate 2 to the power of 128.

2^128 equals about 3.4 x 10^38, which is the total number of unique IPv6 addresses.

Practice

1.

What is the main difference between an IPv4 and an IPv6 address?

easy

A. IPv4 addresses are longer than IPv6 addresses.

B. IPv4 uses eight hexadecimal groups separated by colons; IPv6 uses four decimal numbers separated by dots.

C. IPv4 addresses use letters only; IPv6 uses numbers only.

D. IPv4 uses four decimal numbers separated by dots; IPv6 uses eight hexadecimal groups separated by colons.

Solution

1. Step 1: Understand IPv4 format

   IPv4 addresses have four numbers (0-255) separated by dots, like 192.168.1.1.

2. Step 2: Understand IPv6 format

   IPv6 addresses have eight groups of hexadecimal numbers separated by colons, like 2001:0db8:85a3::8a2e:0370:7334.

3. Final Answer:

   IPv4 uses four decimal numbers separated by dots; IPv6 uses eight hexadecimal groups separated by colons. -> Option D

4. Quick Check:

   IPv4 = four decimals, IPv6 = eight hex groups [OK]

Hint: IPv4 = dots and decimals; IPv6 = colons and hex [OK]

Common Mistakes:

• Confusing the separator symbols (dots vs colons)
• Thinking IPv6 uses only numbers, not hex letters
• Assuming IPv4 addresses are longer than IPv6

2.

Which of the following is a valid IPv4 address?

192.168.1.256
10.0.0.1
172.16.300.5
255.255.255.256

easy

A. 192.168.1.256

B. 10.0.0.1

C. 172.16.300.5

D. 255.255.255.256

Solution

1. Step 1: Check each number range in IPv4

   Each number in IPv4 must be between 0 and 255 inclusive.

2. Step 2: Validate each option

   192.168.1.256 has 256 (invalid), 10.0.0.1 all numbers valid, 172.16.300.5 has 300 (invalid), 255.255.255.256 has 256 (invalid).

3. Final Answer:

   10.0.0.1 -> Option B

4. Quick Check:

   Numbers must be 0-255 in IPv4 [OK]

Hint: IPv4 numbers must be 0 to 255 only [OK]

Common Mistakes:

• Allowing numbers greater than 255
• Confusing IPv4 with IPv6 format
• Ignoring invalid last number in address

3.

What is the expanded form of the IPv6 address 2001:db8::1?

medium

A. 2001:0db8:0000:0000:0000:0000:0000:0001

B. 2001:db8:0:0:0:0:1

C. 2001:db8::0001

D. 2001:0db8::1

Solution

1. Step 1: Understand IPv6 shorthand

   The double colon (::) means one or more groups of zeros are omitted.

2. Step 2: Expand omitted zeros

   Replace :: with enough groups of 0000 to make total 8 groups: 2001:0db8:0000:0000:0000:0000:0000:0001.

3. Final Answer:

   2001:0db8:0000:0000:0000:0000:0000:0001 -> Option A

4. Quick Check:

   :: means fill zeros to total 8 groups [OK]

Hint: Expand :: to enough 0000 groups for 8 total [OK]

Common Mistakes:

• Not filling enough zero groups
• Leaving :: in expanded form
• Mixing uppercase and lowercase hex letters

4.

Identify the error in this IPv6 address: 2001:0db8:85a3:0000:0000:8a2e:0370:7334:1234

medium

A. Too many groups; IPv6 must have exactly 8 groups

B. Invalid characters in groups

C. Groups must be separated by dots, not colons

D. Groups are too short; must be 5 digits each

Solution

1. Step 1: Count groups in the address

   There are 9 groups separated by colons, but IPv6 requires exactly 8 groups.

2. Step 2: Check group format

   All groups use valid hexadecimal digits and colons as separators, so no other errors.

3. Final Answer:

   Too many groups; IPv6 must have exactly 8 groups -> Option A

4. Quick Check:

   IPv6 = exactly 8 groups separated by colons [OK]

Hint: Count groups; IPv6 must have 8 groups [OK]

Common Mistakes:

• Allowing more or fewer than 8 groups
• Confusing colons with dots
• Thinking group length must be fixed at 5 digits

5.

You have the IPv4 address 192.168.1.10 and want to convert it to an IPv6-mapped IPv4 address. Which is the correct IPv6 format?

hard

A. 2001:db8::192.168.1.10

B. ::192.168.1.10

C. ::ffff:c0a8:010a

D. 192.168.1.10::ffff

Solution

1. Step 1: Understand IPv6-mapped IPv4 format

   IPv6-mapped IPv4 addresses use ::ffff: followed by the IPv4 address in hexadecimal.

2. Step 2: Convert IPv4 to hex

   192 = c0, 168 = a8, 1 = 01, 10 = 0a; combined as c0a8:010a.

3. Step 3: Form full IPv6 address

   Combine prefix and hex: ::ffff:c0a8:010a.

4. Final Answer:

   ::ffff:c0a8:010a -> Option C

5. Quick Check:

   IPv4 to hex after ::ffff: prefix [OK]

Hint: Convert IPv4 decimals to hex after ::ffff: prefix [OK]

Common Mistakes:

• Using dotted decimal instead of hex in IPv6
• Placing ::ffff: after IPv4 instead of before
• Not converting IPv4 numbers to hexadecimal