Khan Academy The Internet Study List
The administration of a high school decides to install antivirus software on all of the school computers. What can the antivirus software protect the computers from?
The antivirus software can protect the computers from any malware that it is able to successfully detect.
In 2000, a 15-year-old launched a DDoS attack against the servers of the Yahoo search engine, resulting in users being unable to use Yahoo for an entire hour. Which of these is the most likely explanation for how the DDoS attack brought down Yahoo?
The attack used a large number of compromised computers to send requests to the Yahoo servers, rendering them unable to answer legitimate requests.
How often is the Internet Protocol (IP) used in Internet communications?
It is used whenever two computing devices communicate with each other over the Internet
Computer A wants to send data securely to Computer B using public key encryption. What information do they need from Computer B before Computer A can send the data?
Computer B's public key
Which of these is an accurate description of how the TCP/IP protocols send data around the internet?
Computers split messages into packets, and send them through routers to their final destination. The destination computer acknowledges the receipt of each packet, so that the sending computer can ensure every packet is delivered.
Why does each IP packet contain a sequence number?
Computers use the sequence number to determine the original order of the packets.
When packets are routed on the internet, the route for a particular packet is not pre-determined. Instead, the next hop is decided by each router along the way. How does that increase the fault tolerance of routing?
Each router can pick a connection that's currently working and available.
Many people worry about what would happen if either the Internet or the World Wide Web went down (if they suffered a complete outage and were unreachable). Which of these predictions is correct?
If the Internet went down, the World Wide Web would also go down, since the WWW relies on the Internet protocols.
TCP/IP are the protocols that route data around the internet. What are they each responsible for? 👁️Note that there are 2 answers to this question.
IP is responsible for routing of packets from source to destination across the internet. TCP is responsible for reliable transmission of packets.
In the Internet Protocol (IP), computers send messages to each other through a network of routers, with each message split up into packets. How do routers figure out where a packet needs to go?
Routers look at the IP packet header and use the destination address field.
Comcast, an Internet Service Provider in the US, has many IP addresses that it can assign to its customer's computers. One IP address is 24.128.139.211. Which explanation best describes the hierarchical nature of that address?
The first part of the address (24.128) identifies the network (Comcast) and the second part (139.211) identifies the individual customer.
Consider the website: help.donorschoose.org That website hosts the help center for DonorsChoose, a site where teachers can fundraise for classrooms. Which of these statements are true? 👁️Note that there are 2 answers to this question.
help is a subdomain of donorschoose.org org is a top-level domain
Which of these are a requirement for a computing device to access the Internet? 1. The ability to connect that computing device to another Internet-connected device 2. Registration of the device with ICANN (Internet Corporation for Assigned Names and Numbers) 3. A physical connection that is capable of at least 25 kbps bandwidth
1
Which of these are a requirement for a computer to access the Internet? 1. A wired connection using either an Ethernet or Fiber optic cable 2. A monthly payment to the Internet Engineering Task Force 3. The ability to connect that computer to another Internet-connected device
3
Imagine that you wanted to build a directory that listed the contents of the World Wide Web. What type of item would each listing be?
A Webpage
Tiffany is helping a family member learn how to use Gmail. She notices the website is using a different font and logo, and that the emails are suspiciously worded: Tiffany suspects that gmail.com has been compromised by a DNS spoofing attack. Which of these are good next steps? 👁️Note that there are 2 answers to this question.
Contact the Gmail team via social media or phone Close the Gmail tab
Which description of Internet communication is accurate?
Internet communications are powered by many protocols. One of the most important protocols is the Internet Protocol (IP) since it describes both addressing and routing. Other protocols add layers of functionality on top of that protocol, such as TCP for reliable transmission.
In 2015, the nation of Burundi had an average bandwidth per Internet connection of 11.24 kb/s. In 2016, their average bandwidth was 6.91 kb/s. Which statement is true based on those statistics?
Internet connections in Burundi in 2015 were able to transfer more bits per second than connections in Burundi in 2016.
When a computer loads a webpage, it sends a message to a web server over the Internet. How many Internet protocols are used to send and receive the message?
It always uses multiple protocols.
The following table compares two data transport protocols from the suite of protocols powering the Internet. Can it handle... Protocol 1 Protocol 2 ...lost packets? Yes No ...out of order packets? Yes No ...corrupt packets? Yes Yes What are the most likely identities of Protocol 1 and Protocol 2?
Protocol 1 = TCP, Protocol 2 = UDP
The following table compares two data transport protocols from the suite of protocols powering the Internet. Can it handle... Protocol 1 Protocol 2 ...corrupt packets? Yes Yes ...lost packets? No Yes ...out of order packets? No Yes What are the most likely identities of Protocol 1 and Protocol 2?
Protocol 1 = UDP, Protocol 2 = TCP
A new internet provider ZoomyZoomy is creating advertising for their fast upload speed. Which of these has the correct unit?
Sign up now for an upload speed of 50 Mbps
Processing power: the computer has to do a series of difficult mathematical operations on very large numbers, like generating randomness and checking for prime-ness.
Verifying a computer has a trusted certificate Establishing an encrypted communication channel between 2 computers
Taylor switched WiFi networks from an AT&T network to a Verizon network. He noticed his IP address changed. What's the best explanation for the change?
Verizon has a different set of IP addresses to allocate than AT&T, so Verizon had to give Taylor's computer a different IP address than the AT&T address.
Which of the following statements about IP addresses is true?
When data is sent between devices on the Internet, they identify each other with an IP address.
Which statement is true about packet loss on the Internet?
When two computers are using the Transmission Control Protocol (TCP), the packets that they send to each other can be lost along the way, but they can be recovered via retransmission.
Imagine an internet without the domain name system (DNS). What would that internet be like?
Without the domain name system, we would not be able to use nice URLs like "facebook.com" to visit websites on the internet.
Consider the website: eecs.berkeley.edu That website leads to the Electrical Engineering & Computer Science department of UC Berkeley. Which of these statements are true? 👁️Note that there are 2 answers to this question.
eecs is a subdomain of berkeley.edu edu is a top-level domain
NSFNET was an early internet connecting the computer science departments of universities. In 1986, NSFNET connected 6 departments across the US: Redundancy in a network makes it more fault-tolerant. When two computers in a network are connected by multiple routes, that adds redundancy. Assuming any connection can go down, how many routes are there between NCAR and JVNC?
3 routes
Which of these is not a protocol that powers the Internet?
API, PII
When do Internet-connected computing devices use the Internet Protocol (IP)?
It is used whenever two computing devices send data to each other over the Internet.
Which of these situations describes the invention of a networking protocol?
Leighton proposes a set of rules that describe a way for computers to send data on low-bandwidth connections and lists them in a document. Multiple network administrators agree to the rules and implement them.
In what situations does a computer use multiple Internet protocols to send a message? 1 When it sends an encrypted message 2When it wants an acknowledgement that the destination computer received the message 3When it is loading webpage data
1,2,3
Which of these are a requirement for a computer to access the Internet? 1. A web browser that can load websites and associated multimedia files 2. The ability to connect that computer to another Internet-connected device 3. An encryption key used to secure communications between the computer and other Internet-connected computing devices
2
The Internet Protocol (IP) includes a rule that each message must include a source IP address and a destination IP address. What are the likely consequences of a computer sending a message that does not follow that IP rule? 1 The administrator of the device will receive a message from the Internet Protocol Authority (IPA) reminding them of the proper addressing format. 2 The message will arrive at its destination more slowly since it will be forced to travel along slower network connections for violating the rules. 3 The message may not arrive at its destination at all.
3
In the field of computer networks, what is a protocol?
A documented set of rules that describe the behavior of devices in the computer network
What does it mean for a system to be scalable?
A scalable system can handle an increasing number of users.
What is true about the computing devices exchanging data over the Internet?
All the computing devices that are exchanging data over the Internet are following the rules of the Internet Protocol (IP).
Reina navigates to her bank's website: She notices it looks different from usual - strange fonts and layout, plus it doesn't show how much money is in her banking accounts. Reina checks Twitter and sees reports of a DNS spoofing attack on the banking site: What is a good explanation of this DNS spoofing attack?
Cyber criminals hacked into a DNS server and redirected the mapping for the "banksrus.com" domain name to an IP address that they control.
Pv4 is the first standardized version of the Internet Protocol. IPv4 is gradually being replaced by IPv6, a more scalable version of the protocol. Which feature of IPv4 makes it a less scalable system?
Each IPv4 address is a 323232-bit number. That's enough space for 2^{32} (4.3 \times 10^{9} possible addresses for Internet-connected computing devices (less than the current number of Internet-connected devices).
Emily is trying to use her home computer as a server. She told the IP address to her friend Kolby, and he was able to send messages from his computer to hers. Emily's home just had a power outage, and after a few minutes, the power came back and the internet started working again. However, Kolby can't send messages to Emily's server anymore. Which explanation is the most likely?
Emily's ISP assigned a different IP address to her computer after the power came back on.
HTTPS is a combination of multiple internet protocols that provides secure browsing on the web. What's the best description of how HTTPS combines multiple protocols?
HTTPS retrieves webpages using the HTTP protocol, and uses the TLS protocol to wrap the HTTP requests and responses in a layer of security.
Amazon describes their web services platform like this: Amazon Web Services (AWS) is a highly reliable, scalable, low-cost infrastructure platform in the cloud that powers hundreds of thousands of enterprise, start-up and public sector business with organizations in over 190 countries around the world. What does it mean for the platform to be scalable?
It continues operating when experiencing traffic surges.
Which of these is a way that the Internet Protocol (IP) contributes to Internet communications?
It describes how to route packets of data around the Internet, from router to router, based on a destination address. OR It describes an addressing scheme to uniquely identify each node on the Internet. OR It describes a way to uniquely identify computing devices that are connected to the Internet so that messages can be sent to them.
A startup creates a chatbot that uses artificial intelligence algorithms to have therapeutic conversations with users. Which of these decisions would most directly reveal the most about the chatbot's scalability?
Launching the chatbot in multiple platforms (Android, iOS, and Facebook) on the same day
Rafi is developing an application to send urgent information about global health crises over the Internet to hospitals. He is worried about packets getting lost along the way and the effect that will have on the accuracy of the information. What is his best option for dealing with lost packets?
Rafi can use the Transmission Control Protocol for communication, since TCP has ways to recover when packets are lost.
Ororo typed this URL in her browser's address bar: https://www.nssl.noaa.gov/ After a few seconds, the browser loaded the webpage:Which of these protocols were used by the browser in fetching and loading the webpage? 👁️Note that there may be multiple answers to this question.
TCP IP HTTP
TCP/IP are the protocols that route data around the internet. What are they responsible for?
TCP is responsible for reliable transmission of packets. IP is responsible for routing of packets from source to destination across the internet.
Fen navigates to "https://www.conservationfund.org/" in her browser and sees this on the front page:The front page includes a logo, photos, a video, an interactive slideshow, and a custom font. Which of these resources are loaded using the Hypertext Transfer Protocol? 👁️Note that there may be multiple answers to this question.
The HTML of the webpage The JavaScript code for the slideshow The custom font file Each photo file The logo file The video file
How does the Internet Protocol (IP) fit into the Internet technology suite?
The Internet Protocol is a protocol used in all Internet communication, but other protocols are also used.
Every year during the Christmas holiday, Google hosts a website to help track the path of Santa around the globe. The website goes from zero traffic to millions of visitors in a small period of time. Before the website goes live, site reliability engineers (SREs) are in charge of making sure that the Santa tracking website will be able to withstand the spike in traffic. Which of these strategies is the best way to verify that the Santa tracking website is scalable
The SREs can use Google-owned machines to simulate large amounts of visitors on the website and monitor the website to see how it reacts.
One problem with packet-based messaging systems like the Internet Protocol is that packets might arrive out of order. TCP is a protocol that can deal with out-of-order packets. When used over IP, each packet contains a TCP segment with metadata and data. Which of the following best describes how TCP can reassemble out-of-order packets?
The TCP metadata includes fields that describe where the packet belongs in the sequence.
What is the relationship between the Internet and the World Wide Web?
The World Wide Web is built on top of the Internet.
What is the job of a router during the process of routing on the Internet?
The router's job is to look up the destination IP address in their forwarding table, determine the next router that will get the packet closer to its destination, and send the packet to the router.
Jolene navigates to "https://www.nationaltrust.org.uk/" in her browser and sees this front page: Screenshot of the homepage for The National Trust The website includes a logo, photos, an interactive slideshow, and a custom font. Which of these resources are loaded using the Hypertext Transfer Protocol? 👁️Note that there may be multiple answers to this question.
The slideshow JavaScript library The custom font file Each image file The logo The HTML of the webpage
Which of these best describes the fault tolerance of routing on the internet?
There are multiple routes for each IP packet to follow. A packet can be re-routed if a path becomes unavailable.
The TV show Silicon Valley revolved around a startup and their attempt to bring a new product to market. At one point, the creators of the startup say this about their product: "We're making the world a better place through scalable fault-tolerant distributed databases." What does it mean for the databases to be scalable?
They can continue functioning even if there is a significant increase in the number of operations they must perform.
The following passage describes the Internet but contains a missing adjective: The Internet is built on a stack of communication protocols that are standardized and <???> . As a result, any computer can communicate with other computers on the Internet, without needing to apply for a license from a company. What is the most appropriate adjective to replace <???>?
nonproprietary
The following passage describes the Internet but contains a missing adjective: The Internet is a loosely-organized international collaboration of interconnected networks. Even though the computing devices belong to a wide range of companies, individuals, and governments, all the devices on the Internet can successfully communicate with each other thanks to the <???> nature of Internet protocols. What is the most appropriate adjective to replace <???>?
open
Consider the following statement: The World Wide Web is a web connecting billions of <NOUNS>. What would be the most accurate replacement for <NOUNS>?
webpages
We use modems to connect our home network to the larger network provided by our internet provider (and ultimately the whole internet). Here's a sampling of modems from the last 80 years: Image source: Pratyeka, Wikipedia They look similar, but the bandwidth has been steadily increasing as engineers develop new technologies. Sort this list of historical modems from lowest to highest bandwidth, with the lowest on the top and the highest on the bottom:
"Bell 101" @ 110 bits/s "Bell 103" @ 300 bits/s "Modem 1200" @ 1.2 kbit/s "Modem 2400" @ 2.4 kbit/s "VDSL" @ 52 Mbit/s "MDSL" @ 2.32 Gbit/s
The IPv6 protocol is the most recent version of the Internet Protocol (IP). IPv6 includes several new features related to both addressing and routing. Which of the following features of IPv6 most directly increases the scalability of the Internet?
Each IPv6 address is a 128-bit number. That means there are 2^{128}(3.4 \times 10^{38}) possible addresses for Internet-connected computing devices.
The Transmission Control Protocol (TCP) splits each message into multiple packets. It's possible for packets from the same message to arrive out of order. Which field in the IP packet helps computers put the packets in the original order?
Sequence number
A new high school is built and needs to be connected to the Internet. The IT administrator found these four local providers for Internet services: Provider Bandwidth BeyondNet 100 Mbps SpectralWeb 50 Mbps FinalLink 1000 Mbps TopSat 25 Mbps Which of these comparisons between the providers is correct?
SpectralWeb can transfer 222 times more data per second than TopSat.
The most recent big DNS cache poisoning attacks have been on the cryptocurrency websites MyEtherWallet and Trezor. Those websites help users keep track of their cryptocurrency investments, and they store user credentials that are used for buying and selling. Why would cyber criminals want to DNS spoof a cryptocurrency website?
They can direct those websites to fake websites that ask users for secure information that they can then use on the real website.
Consider the website: blog.gardeningknowhow.com That URL leads to the blog of a gardening tips & tricks website. Which of these statements are true? 👁️Note that there are 2 answers to this question.
blog is a subdomain of gardeningknowhow.com blog is a third-level domain
NSFNET was an early internet connecting the computer science departments of universities. In 1986, NSFNET connected 6 departments across the US: Redundancy in a network makes it more fault-tolerant. When two computers in a network are connected by multiple routes, that adds redundancy. Assuming any connection can go down, how many routes are there between San Diego and Illinois?
3 routes
Over the years, engineers have invented many networking technologies for WANs (wide area networks), connecting large geographic regions like cities and states. The slower technologies are mostly obsolete, but may still be used in developing nations. The following is a sampling of WAN technologies and their bandwidths. Sort the technologies from lowest to highest bandwidth, with the lowest on the top and the highest on the bottom:
"56k line" @ 56 kbit/s "DS0" @ 64 kbit/s "T1" @ 1.544 Mbit/s "VDSL" @ 100 Mbit/s "10 Gigabit Ethernet" @ 9.953 Gbit/s "OC-256" @ 13.271 Gbit/s
Over the years, engineers have invented many networking technologies for LANs (local area networks). Many are still in use, and many of the very slow ones were abandoned long ago. The following is a sampling of LAN technologies and their bandwidths. Sort the technologies from lowest to highest bandwidth, with the lowest on the top and the highest on the bottom: "LocalTalk" @ 230 kbit/s "Econet" @ 800 kbit/s "Omninet" @ 1 Mbit/s "FireWire" @ 400 Mbit/s "Gigabit Ethernet" @ 1 Gbit/s "Omni-Path" @ 100 Gbit/s
"LocalTalk" @ 230 kbit/s "Econet" @ 800 kbit/s "Omninet" @ 1 Mbit/s "FireWire" @ 400 Mbit/s "Gigabit Ethernet" @ 1 Gbit/s "Omni-Path" @ 100 Gbit/s
An online ads distributor AddTheAds claims that its server has lower latency than other ad servers. Which of these claims makes sense?
"Our ad server has a latency of just 40 ms"
These are screenshots of URLs loaded in the Firefox web browser, which uses visual indicators to indicate the security of a web connection. Which of these URLs were successfully loaded over a secure HTTP connection? 👁️Note that there may be multiple answers to this question.
(Locked) https://www.bbc.com
Which statements are true about computing devices? 1.All computing devices are able to run computer programs. 2. All computing devices are capable of being interconnected to form computer networks. 3. All computing devices have ways to store data for later use.
1
Which of the following kinds of computing devices use the Internet Protocol (IP) when sending data over the Internet? 1.A tablet computer 2. A desktop computer 3 A smartphone Choose 1 answer:
1,2,3
Nadia is at an internet cafe in Paraguay, where the download speed is 600 kbps. She's chatting with her friend Jun in Singapore, where the download speed is 60 Mbps. How much faster is Jun's speed than Nadia's?
100x
Josiah used a tool to measure how many bits he could transfer over his home connection to the Internet. This table shows the bits transferred each second: Second Bits transferred 1 900 2 800 3 700 4 1100 5 800 According to those measurements, what is the bandwidth of the connection? Choose 1 answer:
1100 bits/s
NSFNET was an early internet connecting the computer science departments of universities. In 1986, NSFNET connected 6 departments across the US: Redundancy in a network makes it more fault-tolerant. When two computers in a network are connected by multiple routes, that adds redundancy. In this network, how many routes are between San Diego and Cornell?
4 routes
Makayla used a tool to measure how many bits she could transfer over her classroom's Internet connection. This table shows the bits transferred each second: Second Bits transferred 1 5000 2 4500 3 5500 4 4000 5 4500 According to those measurements, what is the bandwidth of the connection?
5500 bits/s
Eliott came up with a scheme for encrypting messages to send to his friend in class. He wanted to use the Caesar Cipher, but his classmates already knew it, so he added a twist on top of it. For each word in the message, he first swaps the first letter of the word with the third letter of the word (if it's long enough), switches the As and the Es, and finally he applies a Caesar Cipher of 14. Demonstration of encryption algorithm, in 3 steps. The first line shows message "MEET_ME_AT_THE_LOCKERS_AT_THREE". "TAMT_ET_AHT_COLKARS_ET_RHTAA". "HOAH_SH_OVH_QCZYOFG_SH_FVHOO". He needs to share an encryption key with his friend before they can decrypt his messages. What would be the best key for this symmetric encryption scheme?
A 3-step explanation of how he encrypted the message (the in-word letter swap, the A and E swap, and the Caesar shift of 14).
Which of the following is the best description of an IP address?
A number assigned to a computing device that can receive data on the Internet
Computer A wants to send data to Computer B using the TCP/IP protocols. What's the best description of how Computer A sends the data?
Computer A splits the data into packets. It does a three-way handshake with Computer B to establish the connection, then sends each packet to the nearest router. If it detects packet loss, it re-sends the missing packets.
In 2016, the ACLU reported that a company called Geofeedia analyzed data from social media websites like Twitter and Instagram to find users involved in local protests and sold that data to police forces. The data included usernames and their approximate geographic locations. Geofeedia claims the data was all publicly available data. For a user that does not want to risk making their geolocation public, which of these actions would NOT reduce the risk?
Cookies
Logan types this URL in his browser's address bar: http://wolverinefoundation.org/ After a few seconds, the browser loads the webpage: Which of these protocols are used by the browser in fetching and loading the webpage? 👁️Note that there may be multiple answers to this question.
HTTP IP TCP
Keung types in the URL for an online email service and sees this in the browser bar: He decides to bypass the error and log into his email anyway, as he's expecting a very important email. What are some consequences of visiting the website with a non-secured HTTP connection? 👁️Note that there are 2 answers to this question.
His ISP can inject advertisements into the emails. A cybercriminal can steal his password.
What is the main advantage of the IP v6 addressing protocol?
IP v6 allows for more addresses than IP v4.
Jelani is a student in a Somalia school, where their internet download speed is 400 kbps. He visits relatives in Oakland, California, and stays at a home where the download speed is 60 Mbps. How much faster is the Oakland home's download speed than the Somalian school's download speed?
150x
Startuppr is a web company that's running their servers out of their garage. Their network administrator is tasked with determining if there is a single point of failure in the network—a router whose outage could cause their servers to lose connection to the Internet. The administrator analyzes this partial diagram of the network: Diagram of network. Each circle is a router, each line is a connection, and the lines with arrows indicate connections to further routers on the Internet. How many single points of failure would the network administrator find?
2
Which of these situations describes a computer network?
A company gives every employee a desktop computer and connects each of the computers to each other using wires, so that they can quickly transfer files and messages.
Bharat runs a computer room at a library. The room has a variety of Internet-connected devices: 20 desktop computers (connected via Ethernet) A 3-d printer (connected via wireless) A security camera (connected via Ethernet) Which of those devices use the Internet Protocol (IP) when sending data through the Internet? Choose 1 answer:
All of them (the desktop computers, 3-d printer, and security camera)
Arthur clicks a link from a chat with his friend that opens "https://www.charitywater.org/". He sees this website load: Which of these best describes how the website loaded?
Arthur's browser sent an HTTP request to the web server that hosts "charitywater.org". The web server sent back an HTTP response with the HTML for the webpage.
Jewel is playing Agar, a multiplayer online game where cells gain mass by eating other cells in a petri dish. She's experiencing "lag": it feels like she doesn't have enough time to move before another cell eats her cell. An online article recommends reducing lag by connecting to a regional Agar server closer to her home. What's the best explanation for why that might help?
If she connects to a regional server, her connection will be lower latency than before.
Each IP packet contains a sequence number. What is the primary purpose of the sequence number?
It helps the receiving computer reassemble the packets.
In the modern age of computers, we cannot use the same symmetric encryption schemes that were used 1000 years ago or even a 100 years ago. What is the best explanation for why we can't use them?
Older encryption schemes are easy to crack with computers, since a computer can quickly perform frequency analysis and try out many keys.
The most time-intensive part of public key encryption is the generation of the key pair. Why does key generation take so long?
Processing power: the computer has to do a series of difficult mathematical operations on very large numbers, like generating randomness and checking for prime-ness.
Public key encryption is considered "asymmetric" encryption due to its use of two keys for encryption and decryption while the Caesar Cipher is considered "symmetric" since it uses the same key for both. Which of these describes how the two keys are used in public key encryption?
The recipient's public key is used to encrypt the data; the recipient's private key is used to decrypt the data.
Devon navigates to "https://www.kidsalive.org/" in his browser and sees this on the front page:
The HTML of the webpage The logo The JavaScript code for the map pop-ups Each graphic file The custom font file
An office receives a copyright infringement notice from their ISP. The notice claims they have evidence that someone in the office illegally downloaded a copyrighted movie on a particular day. The office manager asks around and finds out that, yes, one of the employees did download that movie. How did the ISP likely know about the illegal downloading?
The ISP monitored the internet traffic coming from each of the computers using the office's connection.
Jaime received an email from his favorite movie streaming service. The email stated that all customers were being asked to reset their passwords (due to a security breach) and linked to a webpage with a password reset form. The webpage asks him to confirm his old password and then enter a new password. At that point, Jaime wonders if the email and webpage are part of a phishing scam. He searches the internet and finds other reports of the scam, so he closes the webpage and marks the email as spam. What could have happened if he had filled out the form? 👁️Note that there are 2 answers to this question.
The attackers could try using the "old password" and "new password" to login to Jaime's accounts on other sites. The attackers could use Jaime's "old password" to login to the actual movie streaming website.
Mr. Jones bought a server where his students can upload their homework assignments, and mapped it to the domain "writing302.org". He then acquired a digital certificate for "writing302.org" from a certificate authority and installed it on the server. What does the certificate prove?
The certificate proves that "writing302.org" and its associated encryption key are both owned by the same entity.
Mason receives an email from a law firm called "Baker & McKenzie". The email states that they are scheduled to appear in court and includes a link to view the court notice. Mason is suspicious that this may be a phishing attack, since this is the first they've heard about a court appearance.
They can email
In 2012, cyber criminals launched DDoS attacks on 6 popular US banking websites. They hijacked hundreds of computers and sent traffic that peaked at 60 Gbps. What was the likely effect of the attacks?
Visitors to the websites were unable to use the websites during the attack.
Which of these situations describes the creation of a computer network?
A college campus creates multiple computer labs in different parts of the campus and connects the labs to each other with underground fiber optic cables. Students can save their file on a computer in one lab and still access their files from another lab.
Which of the following is the best description of how routing works on the Internet?
A computer stores the destination IP address in the IP packet header and sends the packet to the nearest router. The router looks at the IP address and decides where to send the packet next based on a lookup table. The next router does the same, until the packet finally ends up at its destination.
The Mozilla Firefox browser gives users three different ways they can disable cookies. The most restrictive option to "disable all cookies" includes a note that it will cause websites to break. What features on websites are likely to break if a user disables all cookies?
A login that works across multiple pages of the website.
Which statement is true about computing devices in a computer network?
Each computing device must be able to send data to the other computing devices.
There is a large difference in IP v6 adoption across the world. These are the IP v6 adoption rates of the top 5 most populated countries, as of October 2018: Country Adoption % China 2.9% India 34% US 34% Indonesia 0.2% Brazil 25.7% Why is it important to encourage countries and their Internet Service Providers to upgrade to IP v6?
If a country's ISPs don't adopt IP v6, they may run out of addresses when too many devices want to use the internet in their country.
Jay is playing BigBalloon, an online multiplayer balloon popping game, and is trying to help his team win during a rumble with another team. However, his attempts to pop balloons aren't working. He's clicking the balloons as soon as he sees them, but the other team's clicks are counting instead. What's the most likely explanation for why that might be happening?
Jay's on an internet connection with too high latency.
Which of these users has the strongest password?
Marjorie combines 5 random words and alternates the casing: "scarves-TOKYO-theme-TEAMWORK-trulia".
DevFest is a conference that wants to make sure it has a reliable connection to the internet. The conference partners with two internet providers, Comcast and Sonic, just in case one of them goes down. The ISP routers then connect to the rest of the internet. Unfortunately, this network is not fault tolerant: there's still a single point of failure. Which router needs to stay available for DevFest to have a working connection to the internet?
Router A
GameCon is a multiplayer gaming tournament that wants to make sure its connection to the internet is reliable. The conference partners with three internet providers (AT&T, Sonic, and Verizon) just in case one of them goes down. The ISP routers then connect to the rest of the internet. Unfortunately, this network is not fault tolerant: there's still a single point of failure. Which router needs to stay available for GameCon to have a working connection to the internet?
Router A
The University of California at Davis has many IP addresses that it can assign to its campus computers. One IP address is 169.237.121.44. Which explanation best describes the hierarchical nature of that address?
The first part of the address (169.237) identifies the network (UC Davis) and the second part (121.44) identifies the campus computer.
IP v4 addresses currently cost more to lease than in the past. What's the most likely explanation for why people are willing to pay more for IP v4 addresses now?
There are very few available IP v4 addresses in the world, and the scarcity increases the demand.
Which of these could be a valid IP v4 or IP v6 address? 👁️Note that there may be multiple answers to this question.
192.168.17.43 2001:0db8:85a3:03eF:7cb3:8a2e:0370:7334
Noemi works out of an office in San Francisco that recently got an upgrade to a 1 Gigabit Fiber internet connection. Ammar works at a company in Pakistan with a 500 Kbps internet connection. How much faster is the SF office connection than the Pakistan office connection?
2000x
Which of these addresses is the kind used by the Internet Protocol (IP) to identify devices that are connected to the Internet?
242.185.95.235
Which of these situations describes a computer network?
A video gaming club sets up six powerful computers in a room and connects them with Ethernet cables to a router. The club members play multi-player games together.
A company moved into a new office space and needs to sign up with an Internet provider. They found these four local providers for business Internet services: Provider Bandwidth ComSat25 Mbps EtherealNet50 Mbps BroadbandUp100 Mbps UberRing12 Mbps How do the ComSat and BroadbandUp connections compare?
The BroadbandUp connection can transfer four times the amount of data per second.
A gardener sets up a network for a garden using a variety of devices: A smart temperature sensor: It runs a program that checks whether the temperature is above or below the target range for that time of day and then triggers the heating or cooling system when needed. A security camera: It uses a machine learning algorithm to detect non-plant motion and sends video footage to a computer. A desktop computer: It generates a graph of the temperature based on data from the temperature sensor and stores video footage from the camera. A wireless router: It uses networking software to enable the sensor, computer, and camera to send data to each other. Which of the devices in the network are considered computing devices?
All of them (the computer, router, camera, and sensor)
Bailey decides to make their own version of the internet. To map domains to IP addresses, he sets up a single computer that stores every mapping. What are the flaws in this system that affect its scalability? 👁️Note that there are 2 answers to this question.
If the computer turns off, no other computer will be able to find out how to map domain names to IP addresses. Once many computers join their internet, the computer may be overwhelmed by requests and not be able to handle all of them in a reasonable amount of time.
An intranet is a private network set up for an organization like a company or university. Here's an intranet with 5 routers labeled A-E: An intranet is more secure, because computers can communicate without using the public internet, but it is often not as fault-tolerant. Imagine that router C needs to send a message to router E. Which of these situations will lead to the message failing to arrive? 👁️Note that there may be multiple answers to this question.
If these 2 connections go down: B to C, C to D. If the connection between D and E goes down.
An intranet is a private network set up for an organization like a company or university. Here's an intranet with 5 routers labeled A-E: An intranet is more secure, because computers can communicate without using the public internet, but it is often not as fault-tolerant. Imagine that router A needs to send a message to router E. What situations will lead to the message failing to arrive? 👁️Note that there may be multiple answers to this question.
If these 2 connections go down: D to E, and B to C. If these 2 connections go down: D to E, and C to E.
Each IP packet contains a destination address. What is the primary purpose of the destination address?
It helps the router know where to send the packet.
In what situations is the Internet Protocol (IP) used?
It is used every time that two computing devices send data to each other over the Internet.
What types of encryption are used in the TLS protocol to ensure secure communication between a client and server?
It starts with public key encryption and then uses symmetric encryption.
Startuppr is a web company that's running their servers out of their garage. Uptime is important to them, so they pay for two internet service providers, Xfinity & Wave. The ISP routers then send their server's packets to the rest of the internet. Unfortunately, this network is not fault tolerant: there's still a single point of failure. Which router needs to stay available for Startuppr servers to stay connected to the internet?
Router A
A gaming company is putting together a gaming tournament called GameCon. Some of the competitions will be with players outside of the conference, so the organizers want to make sure their connection to the Internet is reliable. The organizers partner with three Internet providers (Veryzone, BD&D, and InfiniX). This diagram illustrates their connection to the Internet:Each circle is a router, each line is a connection, and the lines with arrows indicate connections to further routers on the Internet. Unfortunately, this network is not fault tolerant: there's still a single point of failure. Which router needs to stay available for GameCon devices to have a working connection to the Internet?
Router B
Why does each IP packet contain a destination address?
Routers use the destination address to decide where to send a packet
Which are the primary aspects of the domain name system (DNS) that help it scale? 👁️Note that there are 2 answers to this question.
Scalability in the DNS is helped by caching of domain ↔ IP mappings on multiple machines. Scalability in the DNS is helped by the division of labor between root name servers, TLD name servers, and host name servers.
What is the Transmission Control Protocol (TCP) responsible for? What is the Internet Protocol (IP) responsible for?
TCP is responsible for reliable transmission of packets. IP is responsible for routing of packets from source to destination across the internet.
Lavanya is shopping for her first house. At an open house, a real estate agent calls the house a "smart home" and explains that all of the home appliances are also computing devices that are connected together in a computer network. What is the benefit of networking the devices together?
The computing devices can transfer data to each other.
Which of these is the best description of the domain name system (DNS)?
The domain name system associates domain names with IP addresses, like "www.youtube.com" with 208.65.153.251.
Imagine you're trying to explain the domain name system (DNS) to a 5 year old. Which of these metaphors are the most fitting?
The domain name system is like a phone book for the internet.
Rosa is trying to explain to a classmate that IP addresses are hierarchical. Which of these explanations are the best?
The first part of an IP address specifies the network, the next part specifies the individual node in the network.
D'Andre is riding a train with wireless internet service. When he logs online, he sees a warning that the wireless network has limited bandwidth. Which online activities are most likely to be affected by limited bandwidth? 👁️Note that there are 2 answers to this question.
Watching online movies Downloading a large application
