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Computer science > Unit 5 - Networks and the Internet > Flashcards

Unit 5 - Networks and the Internet Flashcards

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1
Q

What does each device that connects to the internet need?

A

A network interface card (NIC)

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2
Q

What is a NIC?

A

Every device that connect to the internet requires one. On computers it is commonly built into the mother board.

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3
Q

What is an IP address?

A

Stand for internet protocol address and is a series of numbers that identifies any device on a network. Computers use IP addresses to communicate with each other both over the internet as well as on other networks.

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4
Q

What is the format of an IP address?

A
  • Each address has a 32-bit number
  • It is usually written in denary with a dot separating each byte
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5
Q

How are data packets used over the internet?

A

When data is sent through the Internet or a TCP/IP network, it is split up into much smaller quantities known as data packets
- These packets each store a smallamount of the data
- Each packet may take a different route through the network

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6
Q

What are routers used for?

A

Routers are used to send data to a specific destination on a network.
- Contains a wireless access point for Wi-Fi connections
- Connects the local network to the internet using a modem
- Assigns IP addresses to each computer that connects to it

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7
Q

What assigns the IP address to a device?

A

A DHCP server (Dynamic Host Configuration Protocol) is built to home routers When a new device connects to the network it is assigned an IP address by the DHCP server

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8
Q

How do you connect to the internet?

A

A router is used to connect a network to the Internet. In a home network, the router is combined with the modem, switch, wireless access point and firewall.In a large business, the router is likely to be a dedicated item of hardware The computers and devices will then connect to dedicated switches or wireless access points.

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9
Q

What is the wireless access point?

A

The wireless access point maybe inbuilt to the router - it allows devices to connect wirelessly

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10
Q

What is the modem?

A

A modem will be part of a home router - it converts data from digital to analogue (radio or optical)

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11
Q

What is a MAC address?

A

Media Access Control Address (MAC address) and if given to an every network device which is unique and stored permanently on the device. Thy are used to send data between two items of hardware on a network such as a computer and router. MAC addresses are used on Ethernet, Wi-Fi and Bluetooth devices.

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12
Q

What is the structure of a MAC address?

A

MAC addresses are 48-bit addresses allowing for 281 trillion (248) possible devices.

MAC addresses are usually written as hexadecimal digits that often have each byte separated by colons or hyphens
An example of a MAC address is:
1f - 38 - 69 - ba - 9f - 0c

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13
Q

What do you think the MAC address identifies, other than the specific device it is stored on?

A

The first three bytes (24 bits) of the MAC address contains a number that represents the manufacturer

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14
Q

What is the second part of the number on the MAC address?

A

The second part of the number is the serial code which is given to the hardware device by the manufacturer

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15
Q

What are the two version of IP address?

A
  • IPv4
  • IPv6
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16
Q

How many bytes make up an IPv4 address?

A

four bytes

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17
Q

What is the format of an IP address usually?

A

They are usually represented as four denary numbers separated by full stops such as:
192.168.52.211

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18
Q

How many IPv4’s are their available?

A

2^32, Which is 4.3 billion addresses

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19
Q

What is the problem with IPv4 address?

A
  • The problem with 32-bit IP addresses is that there aren’t enough of them.
  • As more and more devices are added to the Internet we need an IP address system that can address all of them
  • We therefore need to use a larger binary number than a 16-bit address
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20
Q

How many bytes in a IPv6?

A

sixteen bits

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21
Q

How many devices can be assigned an IPv6 address?

A

2^128 340 trillion trillion trillion addresses

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22
Q

What is the format of an IPv6 address?

A

IPv6 addresses are separated into eight groups each containing four hex digits and separated by a colon – for example:

0123 : 4567 : 90ab : cdef : 0123 : 4567 : 89ab : cdef

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23
Q

What are the differences between an IPv4 and an IPv6? (address size, number of unique addresses, separators, security and assignment of IP address)

A

(Characteristic) (IPv4) (IPv6)
address size - 32-bit | 128-bit
Number of unique addresses - 4.3 bill | 340 trillion trillion trillion
separators - full stops(.) | colons (:)
Security - | improved security
Assignment of IP address - DHCP server | IPv6 devices can configure themselves automatically (Auto-configuration) or DHCPv6

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24
Q

What is a dynamic IP address?

A

This is where the ISP (internet service provider) gives a different Ip address each time the router connects

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25
Q

What is a static IP address?

A

If the IP address is always the same, this is a static IP address

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26
Q

What is an ISP?

A

It stands for an internet service provider which provides the device with the IP address when it connects to the network.

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27
Q

What are some features of web browsers?

A
  • Storing bookmarks and favourites
  • Recording user history
  • Allowing use of multiple tabs
  • Storing cookies
  • Providing navigation tools
  • Providing an address bar
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28
Q

What is the address bar and navigation used for?

A

The address bar allows the user to enter a web address. Navigation is used as previous page, next page and refresh page

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29
Q

What are bookmarks and favourites?

A

Users are able to store a list of bookmarks of sites they want to visit again (known as favourites on microsoft)

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30
Q

What is the user browsing history?

A

Web browsers keep a record of all web pages that users visit

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31
Q

What are tabs used for?

A

Tabs are a user interface feature that allow many web pages to remain open at the same time

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32
Q

What is the internet?

A

The Internet is the large global network of networks. It refers to the physical network infrastructure that is used for the transfer of data

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33
Q

What is the world wide web?

A

The World Wide Web (www) is one service for information sharing that makes use of the Internet. It makes use of the hypertext transfer protocol (HTTP) to send the data. The information stored in Hypertext Markup Language (HTML)

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34
Q

What is the URL structure like?

A

A web address is technically known as a Uniform Resource Locator (URL). A full web address will specify the protocol that needs to be used, the domain name and the webpage or file name

35
Q

What is HTTP?

A

Hypertext Transfer Protocol (HTTP) is the protocol used to send webpages.

36
Q

Why is HTTP not safe to send personal information?

A

It is unencrypted so not safe for sending personal information

37
Q

What is HTTPS?

A

HTTPS (Hypertext Transfer Protocol Secure) is used to send and receive web pages and form data in an encrypted format

38
Q

What is HTML?

A

Web pages are written in hypertext markup language (HTML). The HTML describes the content of the web page

39
Q

What is the main purpose of a web browser?

A

The main purpose of a web browser is, of course, to render (show) web pages

40
Q

How does a browser know which IP address to send a web page request to if it only knows the domain name?

A

It makes use of a domain name system server (DNS server)
The DNS server will translate the domain name into a corresponding IP address

41
Q

Where are websites and web pages stored?

A

Web servers

42
Q

What are web servers?

A
  • These are dedicated machines that are used to serve web pages to devices that request them
  • An ordinary computer can be turned into a web server by installing web server software.
43
Q

What is a commercial web server?

A

Commercial web servers are a physical size that allows many of them to be placed inside a server cabinet. Data centres will be filled with server cabinets

44
Q

What is the domain name system?

A

The Domain Name System is a global system that maps domain names to IP addresses. Browsers ask DNS servers to translate a domain name to an IP address so that they know where to send requests

45
Q

How to web requests work?

A

When the user requests a web page the following happens:
1. The web browser requests the IP address of the domain name from the DNS server
2. The server sends theIP address to the web browser
3. The web browser sends a request for the web page to the IP address
4. The web server sends the web page, in HTML, to the browser

46
Q

What are cookies?

A

Cookies are small amounts of data sent to a web browser. Cookies are designed to personalise your user experience while browsing.

47
Q

Where are cookies stored?

A

The cookie data is stored in a browser file so that it is able to be accessed at a later time

48
Q

What is the purpose of a web server sending cookies to a user’s web browser?

A
  • Saving personal details
  • Tracking user preferences
  • Holding items in an online shopping cart
  • Storing login details
49
Q

What is a persistent cookie?

A

Persistent cookies remain on the computer even if the web browser is closed or the computer is turned off

50
Q

What do persistent cookies?

A

This allows a user to remain logged into a website or items in a shopping cart not to be lost

51
Q

Do persistent cookies expire?

A

The programmer of the websitewill specify the expiry date for the persistent cookie – after that date the cookie is deleted by the browser

52
Q

What are session cookies?

A

Session cookies only last for the browsing session.

53
Q

Do session cookies expire?

A

Yes:
- They don’t have an expiry date which indicates that they are a session cookie
- They are stored temporarily in memory and not on secondary storage
- When the browser window is closed or the computer is turned off, the session cookies will be lost

54
Q

When a user enters a _______________, the domain name is sent to a _______________. The DNS server looks up the _______________ and sends the associated _______________ to the web browser. The web browser now requests the web page to the IP address for the _______________. The web server then sends the web page, written in _______________, to the browser.

Domain name IP address HTML Web serverURL DNS server

A

When a user enters a URL, the domain name is sent to a DNS server. The DNS server looks up the domain name and sends the associated IP address to the web browser. The web browser now requests the web page to the IP address for the web server. The web server then sends the web page, written in HTML, to the browser.

55
Q

Explain the difference between session cookies and persistent cookies

A
  • Session cookies are deleted after the browser window closes
  • Persistent cookies remain on the computer until their expiry date
56
Q

What are some examples of harmful malware?

A

viruses, worms, Trojan horses, spyware, adware and ransomware

57
Q

What is malware?

A

Pieces of software that have been written and coded with the intention of causing damage to or stealing data from a computer system.

57
Q

What is malware?

A

Pieces of software that have been written and coded with the intention of causing damage to or stealing data from a computer system.

58
Q

What is a virus?

A

it is quite like a human virus, this type of malware infects a computer and then replicates itself to be sent to another computer. This transmission can happen where infected files are shared via hard disks drives or sending online.

59
Q

What is a trojan horse?

A

A trojan horse is malware that is hidden away in the code of software that appears to be harmless. Criminal with often hide Trojan horses in illegal or pirate software to obtain user data.

60
Q

What is a worm?

A

A worm operates similarly to a virus, however rather then trying to damage files its simply replicates itself until the computer’s resources are used to their maximum capacity and no further processing can take place, leading to system failure or crashing

61
Q

What is spyware?

A

Spyware is a piece of malware that behaves a little bit like a cookie but instead of benefiting the user it sends data back to a criminal. Spyware collects information about online browsing habits with the user knowing. The spyware may be hidden inside an app, software, file attachment or malicious website

62
Q

What is adware?

A

Adware is not alway malicious, but it almost always involves the instalment process for displaying pop-up adverts while browsing websites, and will install, cookies often without user permission. In the worst cases, new adverts appear faster than the user is able to close them The hacker aims to make money from users clickingon the adverts.

63
Q

What is ransomware?

A

Ransomware is a type of malware that first encrypts the hard drive of a computer. The user is unable to read any files on the computer or run any programs. They need to pay a ransom, usually by a cryptocurrency such as bitcoin. If they pay the ransom, their files should be restored. Otherwise, all files will be deleted. The motivation for this attack is to receive the ransom (money)

64
Q

What is a hacker?

A

A hacking is a user who is seeking to gain unauthorised access to a computer system. They usually do this so that they can access, change or damage the data held on the system being hacked.

65
Q

What is a black-cat-hacker?

A

A hacker who is attempting to gain access to someones computer system for a criminal purpose.

66
Q

How are 2 ways hackers can exploit vulnerabilities?

A

Unpatched software – if software updates and security updates are not installed then the software will be vulnerable

Out-of-date anti-malware – if software, such as antivirus software, isn’t regularly updated then it won’t be able to detect the latest viruses

67
Q

What is social engineering?

A

Social engineering is the ability to obtain confidential information by asking people for it

68
Q

What is phishing?

A

Phishing is a type of social engineering technique. Emails, texts or phone calls are sent to users commonly pretending to be from a bank or website

69
Q

What does phishing try to gain?

A

These messages will try to getpersonal information such as:
- Usernames
- Passwords
- Credit cards details
- Other personal information

70
Q

How to spot for a phishing email:

A

Greeting: The phishers don’t know your name – just your email address, so the greeting is not personalised

The sender’s address is often a variation on a genuine address

Forged link: The link looks genuine, but it the URL attached to it may not link to the website given. Roll your mouse over it to check

Request for personal information: Genuine organisations never do this

Sense of urgency: Criminals try to persuade you that something bad will happen if you don’t act fast

Poor spelling, grammar and tone

71
Q

What is Pharming?

A

Pharming is a term made from the two words: Phishing and Farming
- A users computer or a DNS server are altered so that they match a domain name to an incorrect IP address
- When the browser searches for a web page, it will go to the wrong IP address which is controlled by a hacker
- The hacker will have a web server that serves a fake web page, such as a form for a user to log in to a bank

72
Q

What is a DoS?

A

In a denial of service attack, a hacker will use or infect a computer so that:
- it sends as many requests to the serveras it can (known as a flood) the server can’t respond fast enoughso slows down or goes offline

73
Q

What is a DDoS?

A

A Distributed Denial of Service (DDoS) attack can happen to a website or web server and is designed to cause disruption to website owners. A criminal would use software that can ‘force’ thousands of innocent computers around the world to send a viewing request to a web server. This unofficial network of recruited computers is known as a botnet and would have likely been infected with some form of malware. The flooding of requests sent to a server will overload it and either slow the website right down or cause it to go offline altogether.

74
Q

What is a man-in-the-middle attack (MITM)?

A

A man-in-the-middle attack (MITM) allows the attacker to intercept data communications between the user and server. The attacker can then:
- eavesdrop to find passwords and personal information
- add different information to a web page or other communication such as email

Connecting to unencrypted Wi-Fi makes it easy to perform a MITM attack

75
Q

How can criminals use an USB to download malware onto your device?

A

Criminals sometimes leave a USB stick containing malware in a public place such as a company car park. An unsuspecting employee may pick it up and insert it into their computer. The malware can now install onto the computer so that a hacker can gain access to files, personal data and system resources

76
Q

How to reduce threats on your mobile phones?

A
  • Use the password feature and choose a strong password
  • Make sure the data is encrypted
  • Do not follow links in suspicious emails
  • Think carefully before posting your mobile phone number on public websites
  • Don’t install apps without researching them first – if they require unnecessary extra permissions, don’t install them
  • Delete all information stored on your mobile before discarding
77
Q

What is a brute force attack?

A

This type of attack is designed to try and obtain a user’s password without their consent. It is like a thief taking all available keys (not just yours) and trying them all in a door lock one after the other until the correct key is found. A brute-force attack is where a computer program floods a system with an enormous number of potential passwords or passcodes and uses trial and error to try and find the password that matches. Brute-force attacks target weak passwords created by users.

78
Q

What data interception?

A

When data is being transmitted around a network such as the internet, if it is unencrypted it has the potential to be intercepted on its way to its intended destination. A cyber criminal could use a piece of software called a packet sniffer to examine packets of data as they make their way around a network. The packet sniffer can then feed the contents back to the criminal, who may be able to use the information for fraudulent purpose.

79
Q

define the following:
- Brute-force attack
- Data interception
- Distributed denial of service (DDoS) attack
- Hacking
- Malware
- Pharming
- Phishing
- Social engineering

A

Brute-force attack – trying all possible passwords until the correct one is found
Data interception – obtaining data, without permission, passing through a network
Distributed denial of service (DDoS) attack – flooding a server or network with pointless requests to make it fail or slow down
Hacking – Activities that misuse computer systems/networks
Malware – software that aims to harm computers and/or data
Pharming – Changing DNS records to point to the wrong IP address
Phishing - emails that pretend to be form legitimate companies but actually try to gain personal information
Social engineering – Obtaining confidential information by asking for it - usually making use of confidence tricks

80
Q

What are the ways that vulnerabilities are protected against?

A
  • penetration testing
  • anti-malware software – including anti-virus software
  • firewalls
  • user access levels
  • passwords
  • encryption
  • physical security
81
Q

how does access level mean?

A

This method of protection is hugely important in organisations where there are lots of users accessing a network. Users should be assigned different levels of access depending on the role they have. Administrators of a network have full access and control, and there are several levels of access going down to basic user access which has only limited rights of usage. This method of protection ensures that user behaviour can be controlled while they use a computer on a network

81
Q

how does access level mean?

A

This method of protection is hugely important in organisations where there are lots of users accessing a network. Users should be assigned different levels of access depending on the role they have. Administrators of a network have full access and control, and there are several levels of access going down to basic user access which has only limited rights of usage. This method of protection ensures that user behaviour can be controlled while they use a computer on a network

Computer science (8 decks)

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