CIS 320 Exam 2 (Chpt's 6-10)

What layer deals with what the user sees

Application Layer

What layer is where applications live

Application Layer

What is the only layer that access your computer files?

Application Layer

What is the only layer that interacts with the user

Application Layer

What does HTTP stand for?

Hypertext Transfer Protocol (HTTP)

Which protocol is used for web pages?

Hypertext Transfer Protocol (HTTP)

What is the secure version of HTTP?

HTTPS

What facilitates transfer of files from web server to local server?

Hypertext Transfer Protocol (HTTP)

What is the purpose of a URL?

It’s a character string for people to remember names rather than having to remember IP addresses and port numbers

What does URL stand for?

Uniform Resource Locator

What are Cookies?

A small piece of information stored on your computer by a web browser for later reference

What is the European General Data Protection Regulation?(GDPR)

A law that establishes protections for privacy and security of your data when browsing the internet.

What are the 2 data privacy laws that are some of the strictest in the world?

The Californian Consumer Privacy Act (CCPA) & The European General Data Protection Regulation (GDPR)

What are Dark Patterns?

Intentional design choices that force or nudge the user to do something

What is an HCI?

Human Computer Interaction

When it comes to dark patterns, what is an example of nudging?

A suggestion that encourages users to
click “Accept All” such as highlighting the
button versus not highlighting the Reject All

When it comes to dark patterns, what is Sludge

Excessive and unjustified frictions that
increase the effort and decrease the attention
of a specific choice, such as burying the user in
submenus to understand what “All” they’re
accepting or rejecting

What are the 3 Email Protocols?

1. Simple Mail Transfer Protocol (SMTP)

2. Post Office Protocol (POP)

3. Internet Mail Access Protocol (IMAP)

Where does Simple Mail Transfer Protocol (SMTP) act?

Between Servers

What does Post Office Protocol (POP) & Internet Mail Access Protocol (IMAP) do?

They’re protocols to access email

What are the 3 states of Post Office Protocol (POP)?

Authorization, Transaction, and Update

What are the 4 states of Internet Mail Access Protocol (IMAP)?

Not auth, auth, selected, logout

What does FTP stand for?

File Transfer Protocol

What does File Transfer Protocol (FTP) do?

Its a protocol for transferring files, mostly large files.

Especially useful for uploading web pages to web servers

FTP vs. HTTP

• FTP is bidirectional

• FTP has 2 channels: one for commands and another for data transfer

What is Voice Over IP (VOIP)

Voice calls over broadband internet rather than Plain Old Telephone Service (POTS)

What does Voice Over IP (VOIP) do?

Converts your analog voice into digital signals

What does IM stand for?

Instant Messaging

What are examples of Instant Messaging (IM)?

iMessage, WhatsApp, Snapchat

What is a Bit Torrent?

Rather than accessing a central server to get files, computers can just share files between each other via a “swarm”

How does a Bit Torrent work?

1. One computer has the complete file. (The “seed” computer)

2. Tracker software tracks the swarm, keeping note of who has bits of the file

3. When you join the swarm, you trade pieces of the file you want with pieces you already have

4. Files are called .torrent files

Central Server vs BitTorrent Swarm

Are Bit Torrents legal?

They are legal, but it is illegal to download copyrighted material.

What percent of IPv4 addresses are actually being used?

5% -15%

What are the 3 technologies that let us keep using IPv4 as we transition to IPv6?

• DHCP

• Reusable IP Addresses (RFC 1918)

• Address Translation

What does DHCP stand for?

Dynamic Host Control Protocol

What is Dynamic Host Control Protocol (DHCP)?

• A service that automatically assigns new repossesses IP addresses

What is a benefit of using Dynamic Host Control Protocol (DHCP)?

• It improves efficiency of allocating IP addresses across a network

• It allows a network to reassign IP addresses when they’re not in use

How does DHCP work?

1. DHCP DISCOVER: At bootup, the computer broadcasts a DHCP request for network parameters

2. DHCP OFFER: The DHCP server (such as your home router) sends back an IP address and other parameters, such as lease time

3. DHCP REQUEST: The user computer broadcasts to all DHCP servers which offer it accepted

4. DHCP ACK: The chosen DHCP server responds with an acknowledgment

5. DHCP RELEASE: When shut down, the user sends DHCP release to the server

What are the 5 Steps of how DHCP works?

1. DHCP Discover

2. DHCP Offer

3. DHCP Request

4. DHCP Ack

5. DHCP Release

What are the 3 DHCP Allocation Schemes?

1. Automatic: 1st come, 1st serve, forever

2. Manual: Network admin specifies, forever

3. Dynamic: Temporary leases

What does the GO Programming Language do?

1. Build cloud services and command line interfaces (CLI)

2. Build custom DHCP servers for cloud apps

What are some security issues when it comes to DHCP?

• DHCP itself has no security provisions whatsoever

• DHCP subject to abuse by hackers but also by employees

What are the 3 types of DHCP hacks?

1. DHCP server spoofing (Man-in-the-Middle aka MITM)

2. DHCP starvation aka Denial-of-service (DOS)

3. DHCP or DNS Poisoning attack

How does the DHCP hack, “server spoofing” (Man-in-the-Middle aka MITM) work? (1/3 ways to hack DHCP)

Spoof the server and send forged replies with fake network settings

How does the DHCP hack, “starvation” aka “Denial-of-service (DOS)” work? (2/3 ways to hack DHCP)

Simulate enough devices to drain all the IP addresses from the server, blocking legitimate devices

How does the DHCP hack, “poisoning” work? (3/3 ways to hack DHCP)

Attacker sends fake DNS packets to the server, causing fake entries in the DNS table for target website… redirects user to fake or malicious website intended by attacker

What’s one way to prevent DHCP Hacks?

DHCP Snooping

How does DHCP Snooping work? (One way to prevent DHCP Hacks)

Monitoring your DHCP traffic.

What are Non-Routable Addresses aka Reusable Addresses?

A set of IP addresses defined as reusable as many times as necessary

What must happen for Non-Routable Addresses aka Reusable Addresses to work?

All routers on the entire internet must know which addresses are for reuse.

What are 3 examples of Non-Routable Addresses aka Reusable Addresses?

1. 10.0.0.0

2. 172.16.0.0

3. 192.168.0.0

   Anyone can use these addresses internally within any network without permission from the internet registries

What is Network Address Port Translation (NAPT)

A method of mapping IP addresses from one address block to another while still providing transparent routing to end hosts

It basically translates both IP addresses & port numbers

What are the 2 forms of address translation?

1. NAT: Network Address Translation

2. PAT: Port Address Translation

What does Network Address Port Translation (NAPT) allow for?

It allows for internal networks to support more clients without having separate external, unique IP addresses

Where is Network Address Port Translation (NAPT) configured?

On a routing device such as a router

What is Network Address Translation (NAT)?

• Translates IP addresses

• Allows multiple devices on a local network to appear as if they’re coming from a single public IP address

What is the difference between Network Address Port Translation (NAPT) and Network Address Translation (NAT)?

• NAT primarily translates IP addresses

• NAPT translates both IP addresses and port numbers

What are some benefits from using Network Address Translation (NAT)/ Network Address Port Translation (NAPT)?

1. Increased IP address conservation

2. Hides internal network addresses from outside networks, this provides security

3. Can be configured without requiring changes to hosts or devices on the network.

How is Network Address Port Translation (NAPT) like Google Translate?

Google Translate translates text from one language to another.

NAPT translates network data from the local network (private IP addresses and ports) to the public network (public IP address and ports) and vice versa

What is Address Resolution Protocol (ARP)

• Matches the Ethernet address with a known IP address

• How devices get MAC addresses of other devices on the network

• The sender has an IP address for a receiver but needs their MAC address to send across the physical medium to the next hop

How does Address Resolution Protocol (ARP) work?

1. ARP links addresses at 2 layers: network and data link

2. The sender broadcasts an ARP request on the Local Area Network (LAN), asking for the MAC address associated with a specific IP

3. Computer with the associated IP relies on its MAC

What is Domain Name Service or System (DNS)?

A system that helps the computer find and connect to websites.

It does this by translating human web addresses like www.youtube.com into unique numeric IP addresses that computers use to identify each other on the internet

What is an example of how Domains and Sub-Domains works

The edu domain maintains jurisdiction over usf.edu and usf.edu maintains jurisdiction over business.usf.edu

Essentially the words on the right are parents to the words on the left

What is Domain Responsibility?

Each domain is responsible for translating its sub-domain names to IP addresses

What are the 3 rules of Domain Names?

1. The rightmost part of all domain names is . (dot) which represents the entire internet

2. All domain names are unique & child domain names must be unique within parent domains

3. Each domain has a naming authority and a naming server that is authoritative for its domain

What are examples of open domains?

These are domains that anyone can register

• .com

• .org

• .net

What are examples of limited domains?

These are domains where certain conditions must be met

• .edu

• .gov

What is an example of an industry specific domain?

.aero (for air-travel industry)

What are some examples of countru domains?

• .af

• .cn

• .us

What are some examples of domain registrars?

• GoDaddy

• Google Domains

• Domain.com

Router vs Switch

• Router

  • Connects different networks, such as your home network to the internet

• Switch

  • Connects devices within the same network, like computers or printers.

How do routers choose the best route?

• When there are multiple destinations

• The router compares the “sum of metrics” for all routes (hop count, link costs)

• The path with the lowest metric is chosen

What is it called when a router has to decide which route is the best one to take?

Routing metrics

What does AS stand for?

Autonomous Systems

What is Autonomous Systems (AS)?

A large group of networks with a single routing policy

What is a good way to think of Autonomous Systems (AS)?

Think of it as different clubs (ASs) with their own rules for how members (networks) communicate both within the club and with other clubs on the internet.

What is Route Aggregation in Classless Inter-Domain Routing)?

1. Route refers to a path that data can take through the internet. Each route is identified by an IP address or a range of IP addresses.

2. CIDR is a way of specifying IP addresses and their associated routing information more efficiently.

You're essentially combining several smaller routes into a single, larger route. This is similar to putting smaller items into a suitcase to save space. By doing this, you can make the internet's routing tables more compact and easier to manage.

For example, instead of listing individual IP addresses or smaller address ranges separately, you can group them together using CIDR notation.

What is the purpose of Route Aggregation in Classless Inter-Domain Routing)?

This reduces the size of routing tables, making it faster and more efficient to find the right path for data to travel through the internet.

What is a routing table?

A database that contains information about the available paths or routes in a network.

What is Multi-Protocol Label Switching (MPLS)

Its a smarter, faster mail system for data packets in a network. It simplifies routing and makes data transfer more efficient, which is crucial for modern high-speed networks, including the internet.

Why do we need Multi-Protocol Label Switching (MPLS)?

• Packet headers contain considerably more
  information than is needed simply to choose
  the next hop

• This eliminates unnecessary processing at
  routers by adding a special label to traffic
  going the same place, like luggage tags at the
  airport

What are some disadvantages to decentralized routing?

1. Each router has to independently find its neighbors and forward

2. Requires added functionality in the router to maintain routing tables

What is Software Defined Networking (SDN)?

Use of software to control the network rather than hardware like routers and switches

What are some benefits of Software Defined Networking (SDN)?

• Makes automating network functions easier

• Allows for simpler management of network resources

What is OpenFlow Protocol?

• It was the first SDN protocol

• Its a defined programmable network protocol to help manage and direct traffic

What are the 3 components of Software Defined Networking (SDN)?

1. Controller

2. Southbound APIs

3. Northbound APIs

When it comes to Software Defined Networking (SDN), what is the controller? (Component 1/3 of SDN)

The core element of an SDN architecture, that enables centralized management and control, automation, and policy enforcement across physical and virtual network environments.

When it comes to Software Defined Networking (SDN), what are Southbound APIs? (Component 2/3 of SDN)

They relay info between the controller and the individual network devices such as switches & routers

When it comes to Software Defined Networking (SDN), what are Northbound APIs? (Component 3/3 of SDN)

They relay info between the controller and the applications and policy engines, to which an SDN looks like a single logical network device

What is Intent-Based Networking (IBN)

Giving network admins the ability to define what they want the network to do and having automated software implement those policies to create the desired state

What are the 4 characteristics of Intent-Based Networking (IBN)?

1. Translation & Validation

2. Automated Implementation

3. Awareness of state

4. Assurance of Dynamic Optimization/Remediation

What is Translation & Validation? (Characteristic ¼ of Intent-Based Networking (IBN))

You’re telling your network what you want it to do in plain language. It checks to make sure your requests make sense and can be put into action. For example, if you want the network to be super fast for video calls, this step makes sure that's possible and sets up the right rules.

What is Automated Implementation? (Characteristic 2/4 of Intent-Based Networking (IBN))

It takes your requests and sets everything up automatically, like a smart assistant following your instructions. So, if you said you want a fast network for video calls, it configures the network to make it happen without you having to do the technical stuff.

What is Awareness of State? (Characteristic 3/4 of Intent-Based Networking (IBN))

The network keeps an eye on itself. It's like having sensors all over your house to check if everything's working as it should. If something goes wrong, the network knows and can fix it without you even noticing.

What is Assurance of Dynamic Optimization/Remediation? (Characteristic 4/4 of Intent-Based Networking (IBN))

If things change or if there's a problem (like too many people using the network at once), the network is smart enough to adjust on its own. It keeps things running smoothly, just like a self-driving car that adjusts its speed based on traffic.

What is Simple Mail Transfer Protocol (SMTP)’s purpose and function? (Email Protocol 1/3)

• Purpose: SMTP is used for sending outgoing email messages.

• Function: It takes care of sending your email from your email client (e.g., Outlook, Gmail) to the email server of the recipient. Think of it as the courier that takes your letter to the post office for delivery.

• Characteristics: SMTP doesn't store your emails; it's responsible for the transmission of messages. It's like a one-way street for sending mail.

What is Post Office Protocol (POP)’s purpose and function? (Email Protocol 2/3)

• Purpose: POP is used to retrieve email messages from an email server to your local device.

• Function: When you check your email using POP, it downloads the messages from the server to your device (e.g., computer or smartphone). It's like picking up your physical mail from a post office and bringing it home. POP typically deletes the messages from the server after downloading.

What is Internet Mail Access Protocol (IMAP)’s purpose and function? (Email Protocol 3/3)

• Purpose: IMAP is used for accessing email messages stored on an email server.

• Function: IMAP allows you to view, organize, and manage your email messages directly on the server. When you read an email or move it to a folder using IMAP, those changes are reflected on the server. It's like accessing your mail in a post office where your letters are stored, and you can sort them without taking them home.

What is a simple way to think of the 3 Email Protocols?

Think of SMTP as the sender's protocol for sending emails, POP as the protocol to collect emails from the server to your device, and IMAP as the protocol to view and manage your emails directly on the email server. Each serves a specific role in the email communication process.