How the internet really works Flashcards
(137 cards)
1
Q
What is the internet often represented as?
A
A cloud made up of connections between devices
2
Q
Is the internet a fully distributed network?
A
No, it is decentralized with many centers or nodes
3
Q
What are nodes in a network?
A
Devices that send or receive information
4
Q
What does every node on a network have?
A
An address, typically an IP address
5
Q
What is the role of routers in a network?
A
To connect different networks and direct IP packets
6
Q
What is a server?
A
A node that accepts connections from other nodes and transmits or processes information
7
Q
What shape does a centralized network take?
A
A star with a central point
8
Q
What shape does a decentralized network resemble?
A
A constellation made up of many stars
9
Q
Who are clients in a network?
A
Network nodes that use a service
10
Q
What is a distributed network?
A
A network where all nodes are non-hierarchically connected to each other
11
Q
What is the function of a network card?
A
It handles a device’s connection to the network
12
Q
What is a MAC address?
A
A unique, identifiable address for a device’s network card
13
Q
What is DHCP?
A
Dynamic Host Configuration Protocol, used to assign network addresses
14
Q
What is a network packet?
A
A unit of data consisting of routing information and content
15
Q
What does the Internet Protocol (IP) standardize?
A
The structure of packets and formatting of addresses
16
Q
What are public IP addresses?
A
Addresses with direct access to the internet
17
Q
What are private IP addresses?
A
Addresses with no direct access to the internet, accessible only within private networks
18
Q
What does NAT stand for?
A
Network Address Translation
19
Q
What is the difference between IPv4 and IPv6?
A
IPv4 has approximately 4.3 billion addresses, while IPv6 has 340 undecillion possible addresses
20
Q
What is the format of an IPv4 address?
A
Four blocks of numbers ranging from 0 to 255 separated by dots
21
Q
What is the format of an IPv6 address?
A
Eight blocks of 16-bit numbers separated by colons, often represented in hexadecimal
22
Q
What is the purpose of the Internet Assigned Numbers Authority (IANA)?
A
To manage the allocation of IP addresses
23
Q
True or False: A public IP address must be unique for the entire planet.
A
True
24
Q
Fill in the blank: A device needs a _______ to communicate with other nodes on the network.
A
network address
25
What does a router do when it receives packets from the internet?
Reads packet headers and sends them to the appropriate destination
26
What indicates whether a packet targets a destination device on the same network?
The first part of an IP address
## Footnote
This helps routers determine if the packet should be sent to its own network or forwarded to the next router.
27
What is IP spoofing?
The act of sending data packets while pretending to be another computer by writing a fake sender IP address in the packet tag
## Footnote
This technique allows attackers to hide their true origin.
28
What protocol provides integrity, authenticity, and confidentiality of data packets?
Internet Protocol Security (IPSec)
## Footnote
IPSec uses cryptographic functions to verify packet integrity and authenticity.
29
What do packet headers contain?
Origin and destination addresses
## Footnote
This information is crucial for routing packets through the internet.
30
What are autonomous systems (AS)?
Smaller networks that make up the internet, administered independently
## Footnote
There are approximately 97,000 such ASs.
31
What is the Border Gateway Protocol (BGP)?
The de facto routing standard on the internet that exchanges route information between ASs
## Footnote
BGP helps calculate the shortest and cheapest path for data packets.
32
What is peering in the context of ASs?
An agreement between two ASs to let data traffic pass between them, usually for free
## Footnote
This can reduce costs for data transit.
33
What is the role of Internet Exchange Points (IXP)?
Physical connections of multiple ASs that create faster paths for data traffic
## Footnote
IXPs facilitate faster access to resources across different networks.
34
What does UDP stand for?
User Datagram Protocol
## Footnote
UDP prioritizes speed over reliability.
35
What is the main use case for UDP?
Applications where waiting for delayed packets or error correction isn’t necessary, like video streaming and online gaming
## Footnote
A missing datagram may lead to a distorted experience.
36
What does TCP stand for?
Transmission Control Protocol
## Footnote
TCP provides error correction and ensures ordered packet delivery.
37
What is a three-way handshake in TCP?
A method to establish a communication channel between two applications using SYN, SYN/ACK, and ACK packets
## Footnote
This process ensures reliable delivery of packets.
38
What is QUIC?
Quick UDP Internet Connections, a transport protocol that combines speed and reliability
## Footnote
QUIC uses UDP but includes features to track and order datagrams.
39
What is the Domain Name System (DNS)?
A public, decentralized database that links domain names to IP addresses
## Footnote
DNS allows users to access services using memorable names instead of complex IP addresses.
40
What does a domain name consist of?
At least two sections: a top-level domain (TLD) and a second-level name
## Footnote
For example, in 'en.wikipedia.org', '.org' is the TLD.
41
How many root servers does DNS have?
13 root servers
## Footnote
These servers are maintained by ICANN and provide resilience to the DNS.
42
What happens when a local DNS resolver doesn't know an IP address?
It asks higher-level servers in the DNS hierarchy, starting with the root server
## Footnote
This process continues until the correct IP address is found.
43
What is the difference between gTLD and ccTLD?
gTLD refers to generic top-level domains (e.g., .com, .org), while ccTLD refers to country code top-level domains (e.g., .uk, .ca)
## Footnote
There are over 290 ccTLDs and 1,200 gTLDs.
44
What is the role of the local DNS resolver?
It translates domain names into IP addresses.
45
What happens if the local DNS resolver doesn't know the IP address?
It queries the root server.
46
What does the root server provide if it doesn't know the IP address?
The IP address of the top-level domain (TLD) server.
47
How does caching improve DNS request speed?
It saves previous DNS query results for faster access.
48
What are DNS Security Extensions (DNSSEC)?
They provide a method to authenticate DNS data.
49
What is the trust chain in DNSSEC?
It involves ICANN, TLD registries, and domain owners.
50
Does DNSSEC provide information privacy?
No, DNS requests are still observable.
51
What is DNS over HTTPS (DOH)?
A protocol that encrypts DNS requests using HTTPS.
52
What does HTTP stand for?
Hypertext Transfer Protocol.
53
What is the primary function of HTTP?
To exchange or transfer hypertext.
54
What type of model does HTTP rely on?
Client-server model.
55
What are HTTP status codes?
Codes that report the completion status of HTTP requests.
56
What does a 404 HTTP status code indicate?
Resource not found.
57
Is HTTP an encrypted protocol?
No, HTTP is not encrypted.
58
What does HTTPS stand for?
Hypertext Transfer Protocol Secure.
59
What is the purpose of HTTPS?
To secure HTTP connections using encryption.
60
What cryptographic protocol does HTTPS use?
Transport Layer Security (TLS).
61
What does the TLS handshake establish?
A shared secret key for encryption.
62
What is the Server Name Indication (SNI)?
An extension that allows a client to specify the hostname during a TLS handshake.
63
What are the two main types of cryptographic techniques?
* Signing * Encryption
64
What is the purpose of signing data?
To verify the authenticity of the data.
65
What is encryption?
The process of transforming plaintext into ciphertext.
66
What is the difference between symmetric and asymmetric cryptography?
Symmetric uses one key, while asymmetric uses a pair of keys (public and private).
67
What is transport encryption?
Encryption that secures data traveling over a network.
68
What is a limitation of transport encryption?
It does not encrypt data at rest.
69
What is end-to-end encryption?
Encryption that protects data exchanged directly between users.
70
What is the Double Ratchet Algorithm used for?
End-to-end encryption in messaging apps.
71
What is forward secrecy?
A feature ensuring that intercepted encrypted packets cannot be decrypted in the future.
72
What is the role of certificate authorities (CAs) in TLS?
They issue digital certificates that attest to the ownership of keys.
73
What does a digital certificate contain?
* Server name * Owner's identity * Public key * CA's signature
74
What is the risk associated with certificate authorities?
They can be compromised or forced to issue false certificates.
75
What is forward secrecy?
A feature of cryptographic protocols that ensures session keys are short-lived and not reused, providing enhanced security.
## Footnote
Examples include IPSec, TLS 1.3, OTR chat, Double Ratchet Algorithm, SSH, and Tor.
76
What is cryptography?
The study of and process for making encryption and decryption mathematically secure.
77
What can limit the security and privacy provided by cryptography?
* Policy regulations
* Technical weaknesses of protocols
* Programming mistakes
* Increases in computational power
78
What is a backdoor in cryptography?
A method to weaken encryption that allows access to encrypted data without the standard decryption key.
79
What is the role of the National Institute of Standards and Technology (NIST) in cryptography?
Sets US national standards, including the standardization of weak encryption algorithms.
80
What is a man-in-the-middle (MITM) attack?
An attack where an adversary intercepts and potentially alters communication between two parties.
81
How can users protect themselves from MITM attacks?
By verifying the keys of their communication partners before exchanging messages.
82
What is two-factor authentication (2FA)?
A security process that requires two different forms of identification to access an account.
83
What is network neutrality?
The principle that networks should treat all data the same, without discrimination or charging differently by user, content, website, platform, application, or method of communication.
84
What are some censorship methods used by authorities?
* IP Blocking
* Content Filtering
* Throttling
85
What is URL filtering?
A method that scans URLs for specified keywords and blocks them.
86
What is Deep Packet Inspection (DPI)?
A technology that inspects the data within packets, not just the headers, to identify and monitor network traffic.
87
What is the Great Firewall of China?
A comprehensive system of internet censorship and surveillance employed by the Chinese government.
88
What does HTTP status code 451 indicate?
Content cannot be served for legal reasons.
89
What is censorship monitoring?
The process of monitoring internet connectivity to detect instances of censorship.
90
What is the purpose of NetBlocks?
To monitor and report on internet shutdowns and censorship worldwide.
91
What does OONI stand for?
Open Observatory of Network Interference.
92
What is the purpose of a DNS proxy?
To bypass DNS filtering or blocking implemented by ISPs.
93
How does a Virtual Private Network (VPN) work?
It conceals network traffic and makes DNS requests on behalf of the user.
94
What is Tor?
A network that anonymizes internet traffic by routing it through multiple volunteer-operated nodes.
95
What is a Tor node?
A machine that runs Tor software and helps route traffic through the Tor network.
96
Fill in the blank: Packets travel through intermediary networks and routers that read the packet ______ to route the packets to their destination.
header
97
True or False: Fingerprinting is a technique used to track and extract unique information about a user based on their device and browser settings.
True
98
What does it mean to be pseudonymous online?
To have an online identity that does not directly reveal one's real-world identity.
99
What are some reasons users might want to circumvent censorship?
* Protect personal data
* Ensure privacy
* Maintain anonymity
* Access restricted content
100
What is a Tor node?
A Tor node is a machine within the Tor network that can relay traffic, also known as a relay or hop
## Footnote
As of 2020, there are around 6,500 Tor nodes.
101
What is a Tor circuit?
A Tor circuit is a randomized route that data packets take through three different nodes in the Tor network
## Footnote
This route changes every 10 minutes to enhance anonymity.
102
How does Tor ensure packet anonymity?
Tor wraps data packets in three encrypted layers, ensuring that only the intended node can decrypt its layer
## Footnote
This structure is often compared to an onion.
103
What are exit nodes in the Tor network?
Exit nodes are the final nodes in a Tor circuit that send packets to the clearnet
## Footnote
As of this writing, there are about 1,200 exit nodes.
104
True or False: The exit node can see the contents of unencrypted packets.
True
## Footnote
If the initial request was not encrypted, the exit node can see the package's contents.
105
What is a bridge in the context of the Tor network?
A bridge is a Tor node not listed in the public Tor directory that helps users access the network
## Footnote
Bridges can be blocked if their addresses are discovered by censors.
106
What is an onion service?
An onion service is a hidden service on the Tor network that uses the .onion top-level domain
## Footnote
It keeps traffic end-to-end encrypted.
107
Fill in the blank: An algorithm is an unambiguous set of instructions describing how to _______.
[solve a problem or a class of problems]
108
What are the two levels of automation in algorithms?
The first level is performing tasks impossible to do manually, and the second level is autonomously interpreting results and making decisions
## Footnote
Example: A web search engine's decision to unlist spam content.
109
List some risks of algorithmic decision-making.
* Manipulation of results
* Distortion of reality
* Constraints on freedom of communication
* Surveillance and data privacy threats
* Social discrimination
110
What does the OSI model stand for?
Open Systems Interconnection model
## Footnote
It standardizes the technical communication of telecommunication or computing systems.
111
What is the function of the application layer in the OSI model?
The application layer is where users interact with client applications, like web browsers.
112
True or False: The logical layer is part of the OSI model.
False
## Footnote
The logical layer is not included in the OSI model.
113
What is a filter bubble?
A filter bubble occurs when algorithms filter out content that users do not want to see, reinforcing existing prejudices
## Footnote
This can distort reality by diminishing content variety.
114
What is the role of algorithms in targeted advertising?
Algorithms analyze user data to deliver personalized advertisements
## Footnote
They assess user behavior and preferences to optimize ad relevance.
115
What is the primary concern regarding the governance of algorithms?
The lack of transparency in how algorithms operate and the biases they may perpetuate
## Footnote
This raises questions about human control and accountability.
116
What is the significance of the GDPR?
The GDPR regulates the processing of personal data in the EU and aims to give people agency over their data
## Footnote
It serves as a framework for data protection and privacy.
117
What does the link traffic control layer define?
The transmission of data frames between two nodes directly connected in the physical layer
118
What is included in Layer 1: Physical?
Telecommunication cables, wireless networks, satellite networks
119
What does the physical layer define?
Electrical and physical specifications of the data connection
120
Which devices operate only at the physical layer?
Network adapters, repeaters, and modems
121
What does the infrastructural layer define?
An addressing scheme and how packets are routed over the network
122
What governs the internet's operation and evolution?
Development, coordination, and management of principles, policies, and technical standards
123
True or False: The internet has a central governing body.
False
124
What is the role of the Internet Engineering Task Force (IETF)?
Develops and promotes a wide range of internet standards
125
What type of documents does the IETF produce?
Request for Comments (RFCs)
126
What does the Internet Research Task Force (IRTF) focus on?
Long-term research related to internet protocols, applications, architecture, and technology
127
What organization oversees the technical and engineering development of the IETF and IRTF?
Internet Architecture Board (IAB)
128
What is the mission of the Internet Society (ISOC)?
To promote the open development, evolution, and use of the internet for the benefit of all people
129
What does ICANN coordinate?
The internet’s system of unique identifiers, including IP addresses and top-level domain space
130
What does the Institute of Electrical and Electronics Engineers (IEEE) develop?
International standards for telecommunications hardware, including Ethernet, Bluetooth, and Wi-Fi
131
Fill in the blank: The logical layer is a set of procedures that ensure that all processes necessary to make the internet function actually _______.
[work]
132
Name one organization that develops internet protocols and standards.
IETF
133
What agency is responsible for coordinating the global use and access to the radio spectrum?
International Telecommunication Union (ITU)
134
What issues dominate the content layer of internet governance?
Privacy, encryption, freedom of speech, human rights, and intellectual property
135
What is the purpose of the Internet Governance Forum (IGF)?
To serve as a global forum for discussion on content layer issues
136
What percentage of the global population is using the internet?
53.6 percent
137
What drives the social and economic aspects of the internet?
States and governments, private bodies and businesses, policy organizations, citizens
