Unit 2: The Internet (APCSP '25-'26 code.org)

What is the purpose of DNS?

• It assigns a unique address to every device on the Internet.
• It returns the IP address given the name of a website.
• It forwards a message from one machine to another.
• It has more bits so you can make a longer, unique address.

What is the purpose of a router?

• It assigns a unique address to every device on the Internet.
• It returns the IP address given the name of a website.
• It forwards a message from one machine to another.
• It has more bits so you can make a longer, unique address.

Why was IP v4 replaced by IP v6?

• IP v6 is easier to use.
• IP v4 does not work on old hardware.
• IP v4 was not encrypted.
• We were running out of IP v4 addresses.

Transmission Control Protocol (TCP):

• Breaks messages into packets and addresses them

• A DNS attack in which numerous pings are made to the same IP, causing it to crash

• Protocol used by the World Wide Web. It describes how messages are formatted and interchanged, and how web servers respond to commands.

• Provides reliable, ordered, and error-checked delivery of a stream of packets on the internet

Internet Protocol:

• Breaks messages into packets and addresses them
• A DNS attack in which numerous pings are made to the same IP, causing it to crash
• Protocol used by the World Wide Web. It describes how messages are formatted and interchanged, and how web servers respond to commands.
• Provides reliable, ordered, and error-checked delivery of a stream of packets on the internet

Which type of attack is this: 
Redirecting a site's IP to a similar, fake site to collect user input information?

• DDOS
• DNS hijacking/spoofing
• Wire tapping

Given the following network diagram, what is the minimum number of connections that must be broken or removed before computer E can no longer communicate with computer B?

• 1
• 2
• 3
• 4

Which of the following statements about packets is true? 

• Packets must be sent in order so they can be reassembled at the end host. 
• Packet switching results in a sustained, single connection between two hosts.
• All packets must pass through a centralized router to be verified.
• None of these statements are true. 

The world transitioned into using IPv6, a newer version of the IP protocol that uses 128-bit addresses instead of 32-bit addresses used by IPv4. What was the main problem that IPv6 was created to solve?

• IPv6 would allow problems with IPv4's address hierarchy to be resolved

• 32-bit addresses could not ensure that every internet-connected device can receive a unique IP address
• 32-bit addresses could not accommodate the increased size and amount of data traveling on the Internet as it has grown in popularity
• IPv4 proved unreliable in some cases where network redundancy could not be ensured

Which of the following protocols is primarily used to establish a secure connection between browsers and servers so that no data is lost?

• HTTP
• SMTP
• SSL/TLS
• TCP/IP