Google IT Support Professional Certificate Notes.pdf

Google IT Support Professional Training (took 137hrs) Course #1: Technical Support Fundamentals 10 Supplemental Reading on Connector Types 12 USB 2.0, 3.0 & 3.1 12 Micro USB, USB-C & Lightnin...

Google IT Support Professional Training (took 137hrs) Course #1: Technical Support Fundamentals 10 Supplemental Reading on Connector Types 12 USB 2.0, 3.0 & 3.1 12 Micro USB, USB-C & Lightning Port 12 Communication Connectors 12 Device Connectors 13 Punch Down Blocks 13 Key Takeaways 13 When repairing mobile devices, 14 Mobile Display Types 14 Liquid Crystal Display (LCD) 14 In-Plane Switching (IPS) 14 Twisted Nematic (TN) 14 VA-Vertical Alignment 14 Organic Light Emitting Diodes (OLED) 15 Active Matrix Organic Light Emitting Diode (AMOLED) 15 Inorganic mini-LEDs (mLEDs) 15 Inorganic micro-LEDs (μLEDs) 16 Key takeaways 16 What is a cyclical redundancy check? 16 Boot Methods 16 Internal method 16 External tools 17 External bootable devices include: 17 Window OS or Linux OS 17 macOS 17 Key Takeaways 17 Boot Methods Best Practices 17 The boot process 18 Configuring boot options 18 Boot method options 18 External options 19 Internal options 19 Key Takeaways 19 Windows 10 and 11 Feature Matrix 20 Features 20 Services and settings 20 Key takeaways 20 Common Scripting Solutions 21 Scripting languages 21 Scripting uses - finding the right tool for the job 22 Security risks of using scripts 22 Key takeaways 22 Wolcott | 1  Technical Interview Prep 23 Course #2: The Bits and Bytes of Computer Networking 25 TCP/IP Five-Layer Network Protocol 25 Dissection of a TCP Segment (below) 28 Non-routable IP Addresses: 28 Socket States 28 System Ports versus Ephemeral Ports 29 TCP ports and sockets 29 Three categories of ports 29 How TCP is used to ensure data integrity 30 Port security 30 Key takeaways 30 Broadband Protocols 31 Point to Point Protocol (PPP) 31 Configuring PPP 31 Sub-protocols for PPP 31 Encapsulation 32 Point to Point Protocol over Ethernet (PPPoE) 32 Key takeaways 32 Wan Protocols V2 32 Physical versus software-based WANs 33 WAN optimization 33 WAN Protocols 33 Wi-Fi 6 34 Benefits of Wi-Fi 6 34 Capabilities of Wi-Fi 6 35 Wi-Fi 6E extends Wi-Fi 6 into 6 GHz 35 Key takeaways 35 Resource for more information 35 Alphabet Soup: Wi-Fi Standards 35 Wi-Fi 2.4 GHz and 5 GHz frequencies 36 2.4 GHz 36 5 GHz 36 IEEE 802.11 standards 36 IEEE 802.11 major updates list: 37 IoT Data Transfer Protocols 38 Data protocol models used with IoT 38 IoT data protocols at the application layer 38 WPA3 Protocols & Encryption 39 WPA3-Personal 39 WPA3-Enterprise 40 Key takeaways 40 Wireless Network Protocols for IoT 41 IoT wireless network protocols at the physical layer 41 Ways to investigate connection issues: 42 Supplemental Reading for IPv6 and IPv4 Harmony 42 Wolcott | 2  IPv6 and IPv4 harmony 42 Tunneling 43 Three types of tunnels 43 Key takeaways 43 Course #3: Operating Systems and You: Becoming a Power User 44 Windows Powershell Commands [note that cmd.exe commands are from DOS]: 44 Linux CLI Commands: 46 Common Root Directory Subfolders 48 Files and Permissions 48 Package & Software Management 48 Windows Software Packages 48 Installation Package 49 Portable Executable 49 Self-extracting Executable 49 App Packager 49 Microsoft Store 49 Key takeaways 50 Resources for more information 50 Mobile App Distribution 50 How apps are distributed 50 Apple mobile apps 50 Custom Apple apps 51 Android mobile apps 51 Resources for more information 53 Mobile App Packages: App Updates 53 How to update apps 53 Android mobile apps 53 Apple mobile devices 54 Resources for more information 54 Mobile Device Storage Space 54 Apple mobile devices 55 Android mobile devices 55 DLL Files and Windows Package Dependencies 56 Dynamic link library (DLL) 56 DLL dependencies 56 Side-by-side assemblies 57 Linux Package Dependencies 57 The dpkg command 58 Syntax 58 Additional Debian package managers 58 Package Managers 59 Software Managers 59 Linux Devices and Drivers 59 Installing a device in Linux 60 Device autodetect with udev 60 Installation through a user interface - GNOME 60 Wolcott | 3  How to check if a device is installed 60 Windows Update 61 Types of Windows updates 61 Installing updates 62 Automatic updates 62 Manual updates 62 Key takeaways 62 Linux Update 62 Linux kernel 63 Updating Ubuntu Linux distribution 63 Key Takeaways 63 Resources for more information 63 File Systems 64 How to Format a Filesystem 64 Disk Partitioning and Formatting in Windows 64 DiskPart 64 Cluster Size 65 Key Takeaways 65 Don’t forget to mount/ unmount external filesystems! 65 Mounting and Unmounting a File System in Linux 65 File system table (fstab) 65 Fstab options 66 Editing the fstab table 66 Windows Swap Space 69 Windows Paging Files 69 Page file sizing 69 Linux Swap Space 71 Process Management 71 Resource Management 71 Resource Monitoring in Linux 71 Load in Linux 72 Load average in Linux 72 Top 72 Key Takeaways 73 Remote Connections in Windows 73 SSH 73 OpenSSH 73 Common SSH Clients 73 Key Takeaways 74 Resources 74 Virtual Machines 74 How VMs work 74 VM software 75 Key takeaways 75 More resources 75 Logs 75 Wolcott | 4  OS Deployment Methods 76 Hard disk duplicator 76 Disk cloning software 76 Methods for deploying disk clones 77 Flash drive distribution 77 The Linux dd command 77 Key takeaways 77 Windows Troubleshooting 77 Solving the problem 78 An example scenario 78 Accessing logs through the Windows GUI tool 78 Interpreting the log file 78 Key takeaways 79 Windows Troubleshooting Tools 79 Troubleshooting tools for Windows 79 Common problems in Windows 80 Resources 81 Example Troubleshooting a problem in Windows 81 Resources 82 Course #4: System Administration and IT Infrastructure Services 84 Change Management 84 IT change management plans 84 Change board approvals 85 User acceptance 85 Recording your actions 86 Reproduction Phase (Roadmapping a user-end error) 86 Week 2: IT Infrastructure Services 86 Remote connections 87 Remote access software for IT management 87 Remote access software 88 Third party tools 88 Resources for more information 89 PowerShell Managing Services 89 Linux Shell Managing Services 89 Configuring DNS w/ Dnsmasq (in linux) 89 Configuring DHCP w/ Dnsmasq (in linux) 89 Popular Email Protocols: 90 Spam Management and Mitigation 90 Types of spam 90 Spam mitigation and management solutions: 91 Resources for more information 91 Web Server Security 91 Mobile Synchronization 91 Mobile synchronization as backup 92 Mobile synchronization for collaboration and productivity platforms 92 Sync Microsoft 365 to a mobile device 92 Wolcott | 5  Sync Google Workspace to a mobile device 92 Key takeaways 93 Print Services 93 Printing languages 93 Printer Control Language (PCL) 93 PostScript (PS) 93 Basic printer configuration settings 93 Sharing a printer on a network 94 Network scan services 94 Printer security 94 Key takeaways 94 Resources for more information 95 Printers 95 Printer technologies 95 Viewing your printers 96 Installing a printer 96 Virtual Printers 97 Printer Sharing 97 Network Printers 97 Print Servers 97 Nice Troubleshooting Printers Module 97 Common Printer Types Module 98 Platform Services 98 Load Balancers 98 Load balancing terminology 98 Example ADC process for load balancing 99 Load balancing types 99 Load balancers in cloud environments 100 Load balancers in physical environments 100 Common Cloud Models 100 Types of cloud services 100 Software as a Service (SaaS) 100 Platform as a Service (PaaS) 100 Infrastructure as a Service (IaaS) 101 VPN as a Service (VPNaaS) 101 Function as a Service (FaaS) 101 Data as a Service (DaaS) 101 Blockchain as a Service (BaaS) 101 Four types of cloud computing 101 Key Takeaways 101 Resource for more information 101 Managing Cloud Resources 102 Directory Services 102 Windows Files 103 Linux Files 103 How Windows Repairs Files 103 Wolcott | 6  How Linux Repairs Files 103 Linux File System Repair 103 Symptoms of data corruption 103 Causes of data corruption 104 Data corruption repair 104 The fsck command 104 How to use the fsck command 105 How to run fsck on the next boot or reboot 106 Edit & Create Group (GPO) Policies using GPMT 106 Group Policy Troubleshooting 106 Mobile Device Management (MDM) Systems 107 Data Recovery 107 Deploying Software/ Files to Different Groups 107 Course #5: IT Security: Defense against the Digital Dark Arts 109 Starting Here from Week 2 (Go over Week 1 notes on Coursera) 109 Physical Privacy and Security Components 109 CIA Principle: Confidentiality 109 Something you are: Biometrics 109 Fingerprint scanning 109 Facial recognition 109 Iris and Retinal scanning 110 Somewhere you are: Geolocation 110 Geofencing 110 Global Positioning Systems (GPS) 110 Indoor Positioning Systems (IPS) 110 Near-field communication (NFC) and scanners 110 Something you do: Gestures and Behaviors 110 Key takeaways 111 Resources for more information 111 Kerberos (Big detailed stuff) 112 Single Sign-On 112 Authorization and Access Control 112 Mobile Security Methods 112 Common mobile security threats and challenges 112 Security measures used to protect mobile devices 113 Screen Locks 113 Remote wipes 113 Policies and procedures 113 Key takeaways: 113 Top 4 mobile security threats and challenges for businesses 114 https://www.techtarget.com/searchmobilecomputing/tip/Top-4-mobile-security-threats-and-challenges-for-busi nesses 114 The ultimate guide to mobile device security in the workplace 114 https://www.techtarget.com/searchmobilecomputing/The-ultimate-guide-to-mobile-device-security-in-the-work place 114 What Is the CIA Triad? 114 Wolcott | 7 https://www.f5.com/labs/articles/education/what-is-the-cia-triad 114 Understanding the significance of the three foundational information security principles: confidentiality, integrity, and availability. 114 OAuth 114 Accounting 114 Walkthrough of “One of the more secure wireless configurations” 115 IEEE 802.1X 115 IEEE 802.1X Protocol 115 Authentication 116 Authentication methods 116 Shared Key authentication methods 116 Key takeaways 116 WEP 116 Alternatives to WEP (That were WEP hardware compatible) 117 Network Monitoring 117 Unified Threat Management (UTM) 117 UTM options and configurations 117 Stream-based vs. proxy-based UTM inspections 118 Benefits of using UTM 119 Risks of using UTM 119 Key takeaways 119 Home Network Security 119 Common security vulnerabilities 119 Keeping home networks secure 120 Key takeaways 120 Host-Based Firewalls 120 Logs, Analysis, Incident Investigation 120 Windows Defender Guide 120 ]Microsoft 365 Defender 120 Microsoft 365 Defender services 121 Using Microsoft 365 Defender 121 Microsoft 365 Defender in action 121 User Account Control (UAC) 122 Resources for more information 122 Anti-Malware Protection 123 Disk Encryption 123 Supplemental Reading on Disk Encryption Tools 123 Browser Hardening 123 Identifying trusted versus untrusted sources 123 Secure connections and sites 124 Password managers 124 Browser settings 125 Key takeaways 125 Resources for more information 125 WEEK 6 BABAY! 125 Data Destruction 125 Wolcott | 8  Recycling 126 Physical destruction 126 Outsourcing 126 Key Takeaways 127 Resource for further information 127 Incident Response 127 Regulated data 127 Digital rights management (DRM) 128 End User Licensing Agreement (EULA) 128 Chain of custody 128 Key takeaways: 129 BYOD 129 Bring your own device (BYOD) 129 BYOD Threats 129 Solutions 130 Key takeaways 130 Resources for more information 131 Final Project - Sample Submission 132 Authentication 132 External Website 132 Internal Website 132 Remote Access 132 Firewall 132 Wireless 132 VLANs 132 Laptop Security 132 Application Policy 133 User Data Privacy Policy 133 Security Policy 133 Intrusion Detection or Prevention Systems 133 Bonus Week! JOB SEARCHING 134 Wolcott | 9 Course #1: Technical Support Fundamentals How much info/ what’s the highest number you can make with a 2x bit number? 28 = 8 bits 22 23 24 25 26 27 28 216 224 232 264 2128 2256 4 8 16 32 64 128 256 65,536 16,777, 4,294,967,296 18,446,744,073, 340,282,366,920,93 1.158 x 10^77 709,551,616 8,463,463,374,607, 216 431,768,211,456 Character Encoding is what translates binary into things humans can perceive. (ASCII, UTF-8 for text and even RGB for color) Hard Disk Drives are less expensive than Solid State Drives Computers use DC (Direct Current) voltage. If your outlet has a higher voltage than your device charges with, it’ll explode. The “water pressure” of an electric cable is Voltage (wall outlets have voltage) The amount of electricity “coming out” is “Amperage” or “Amps” Watts are a combo of Volts and Amps, which means total electricity throughput. Watt is a a combo like how meters per second is a combo of distance and time (These combos are called “vectors” in math) Most desktops can work with a 500w power supply, but high performance shit like video editing or gaming may benefit from a higher wattage. Power standards for input voltages can vary from country to country. The most common voltage inputs are 110-120 VAC and 220-240 VAC. VAC stands for volts of alternating current. The computer’s power supply plugs into an adapter on the computer’s motherboard. The wiring for this connection uses color coded wires. Each wire color carries a different voltage of electricity to the motherboard or serves as a grounding wire. A standard ATX motherboard power adaptor has either 20-pins or 24-pins to connect these wires. The 20-pin design is an older technology. The 24-pin connector was developed to provide more power to support additional expansion cards, powerful CPUs, and more. The 24-pin connector has become the standard for today’s personal computer power supplies and motherboards. The power supply will have multiple connectors that plug into the motherboard, hard drives, and graphic cards. Each cable has a specific purpose and delivers the appropriate amount of electricity to the following parts: Connections from a PC power supply (ATX 2) 1. Floppy disk drive (obsolete) 2. "Molex" universal (e.g. IDE hard drives, optical drives) 3. SATA drives 4. Graphics cards 8-pin, separable for 6-pin 5. Graphics cards 6-pin 6. Motherboard 8-pin 7. Motherboard P4 connector, can be combined to 8-pin mainboard connector 12V 8. ATX2 24-pin, divisible 20+4, and can therefore also be used for old 20-pin connections Wolcott | 10  All rechargeable batteries have a lifespan measured in charge cycles. Wolcott | 11  to transfer 40 megabytes of data in a second, you need a transfer speed of 320 megabits per second. Thus, the formula for bytes-to-transfer in a second its (Bytes) times 8 = (Necessary megabits per second in order to transfer all the Bytes in one second) It’s actually called the CMOS battery (a correction from the coursera vids) Supplemental Reading on Connector Types A computer has many physical ports or connectors. You can use these connectors to connect devices that add functionality to your computing, such as a keyboard, mouse, or monitor. These external devices are called peripherals. IT often works with and troubleshoots these peripherals, so it is helpful to understand the types of connectors. This reading will cover different types of connectors and their uses. USB 2.0, 3.0 & 3.1 USB connectors transfer data and power to devices connected to a computer. USB connectors are the most popular connectors for all types of peripherals. There are three generations of USB type A connectors in use today: USB 2.0, 3.0, and 3.1. Here are the differences between the three generations: USB 2.0: Black port on the computer, 480 MBps transfer speed USB 3.0: Blue port on computer, 5 Gbps transfer speed USB 3.1: Teal port on the computer, 10 Gbps transfer speed USB ports are backwards compatible, meaning a USB port can connect any of the three generations of USB type A connectors. The connected cable will determine the speed of data transfer. Connecting a USB 3 to a USB 2 port will result in 480 megabytes per second of speed. Micro USB, USB-C & Lightning Port Micro USB, USB-C, USB4 (Thunderbolt), and Lightning Ports are smaller connectors that carry more power than older USB connectors and have faster data transfer speeds. These connectors are used for devices like smartphones, laptops, and tablets. Micro USB is a small USB port found on many non-Apple cellphones, tablets, and other portable devices. USB-C is the newest reversible connector with either end having the same build. USB-C cables replace traditional USB connectors since they can carry significantly more power and transfer data at 20 Gbps. USB4 uses Thunderbolt 3 protocol and USB-C cables to transfer data at speeds of 40 Gbps and provide power as well. Lightning Port is a connector exclusive to Apple that is similar to USB-C. It is used for charging and connecting devices to computers, external monitors, cameras and other peripherals. Communication Connectors Different cable connectors are used to share information between devices and connect to the internet. IT professionals maintain network systems that use different types of communication connectors. Wolcott | 12  Plain Old Telephone Service (POTS) refers to cables transmitting voice through twisted copper pair wires. Landline telephones, dial-up internet, and alarm systems use POTS. The RJ-11 (Register Jack 11) connector is used for POTS. Digital Subscriber Line (DSL) provides access to high-speed networks or the internet through telephone lines and a modem. The RJ-45 connects a computer to network elements and is mostly used with ethernet cables. Cable Internet uses a cable TV infrastructure and a modem to provide high-speed internet access to users. An F type connector is commonly used with cable modems.. Fiber-optic cables contain strands of glass fibers inside an insulated casing that send data long-distance and allow for higher-bandwidth communication. The major internet providers use fiber-optic cables for high-speed internet service. Device Connectors IT professionals will encounter legacy devices that still use older connectors such as DB89 and Molex. DB89 connectors are used for older peripherals like keyboards, mice, and joysticks. An IT professional may still encounter a DB89 connector for external tools a computer uses and should recognize the cable to connect to the appropriate port. Molex connectors provide power to drives or devices inside the computer. Molex connectors are used for connecting a hard drive, disc drive (CD-ROM, DVD, Blu-ray), or a video card. Punch Down Blocks A punch down block is a terminal strip used to connect telephone or data lines. Punch down blocks are a quick and easy way to connect wiring. IT professionals use punch down blocks to change a wire or make a new connection for a telephone system or Local Area Network (LAN). These are the most common cables and connectors. As technology advances, these cables and connectors will also change. Key Takeaways IT professionals need to be familiar with cables and connectors used to attach peripheral devices to computers. USB connectors are the most common connector type and they transfer data and power to devices connected to a computer. Communication connectors, such as RJ-45 and fiber optic cables, connect devices to the internet and one another. IT professionals may encounter legacy devices that use older connectors such as DB89 and Molex. Punch down blocks are terminal strips used to connect telephone or data lines. Wolcott | 13 When repairing mobile devices, Protect against static discharge, use the right tools, keep parts organized and labeled, taking pictures along the way can help a lot too, follow vendor documentation, and test the device to make sure it still works. Mobile Display Types In this reading, you will learn about several types of displays used in modern mobile devices and monitors. As an IT Support professional, you may need to troubleshoot various types of displays. This might involve repairing damaged mobile device screens. You may even be responsible for selecting and ordering mobile devices for the employees of an organization. In your IT job role, you should have a basic understanding of the technology behind modern displays, as well as their common uses, positive features, and negative flaws. The top two technologies used in mobile system displays are Liquid Crystal Displays (LCD) and Light Emitting Diodes (LED). Liquid Crystal Display (LCD) LCDs use liquid crystal technology. Liquid crystals have the properties of both a liquid and a solid. The crystals can be aligned in a variety of patterns and manipulated with electricity. How the liquid crystals are arranged and manipulated inside display panels affects refresh rates, image quality, and display performance. LCDs require backlighting, often provided by LEDs. Displays that need backlighting are also called non-emissive or passive displays. The backlighting unit (BLU) requires extra space, which makes LCD panels thicker and less flexible than other displays. Polarizers on either side of the liquid crystal layer control the path of the backlight to ensure the light is aimed toward the user. The following are common LCD display types used for mobile devices: In-Plane Switching (IPS) How it works: In IPS displays, the liquid crystals are aligned horizontally to the screen. Electricity is passed between the ends of the crystals to control their behavior. Uses: IPS technology is used in touch screen displays and high-end monitors. They are often used for design, photography, video/film editing, animation, movies, and other media. They can also be used for games that rely on color accuracy and wide viewing angles, as opposed to speed. Positives: IPS displays provide vibrant colors, high quality graphics, and wide viewing areas. Additionally, they offer excellent color reproduction, accuracy, and contrast. Negatives: IPS displays are expensive. They have low refresh rates and slow response times. However, response times have been improving as the IPS technology evolves. IPS displays can be affected by “IPS Glow”, where the backlight is visible from side viewing angles. Twisted Nematic (TN) Twisted Nematic (TN) is the earliest LCD technology that is still in use today. The term nematic, which means “threadlike,” is used to describe the appearance of the molecules inside the liquid. How it works: In TN displays, the liquid crystals are twisted. When voltage is applied, the crystals will untwist to change the angle of the light they transmit. Uses: TN displays are appropriate for basic business use (e.g., email, document, and spreadsheet applications). They are also used for games that need rapid display response times. Positives: TN displays are low cost, easy to produce, have excellent refresh rates, response times, and resolutions. They are versatile and can be manufactured for any size and/or shape. Negatives: TN displays have narrow viewing angles, low image quality, color distortion, and poor color accuracy and contrast. VA-Vertical Alignment Wolcott | 14  How it works: In VA displays, the liquid crystal molecules are vertically aligned. They tilt when electricity passes through them. Uses: VA displays are intended for general purpose. Provides mid-range performance for graphic work, movies, and TV. Positives: VA displays offer great contrast, deep black shades, and fast response times. They are mid-range quality for refresh rates, image quality, viewing angle, and color reproduction. Negatives: On VA displays, motion blur and ghosting occurs with fast-motion visuals. Organic Light Emitting Diodes (OLED) OLEDs are diodes that emit light using organic (carbon-based) materials when electricity is passed through the diodes. Displays that are able to convert electricity into light are called emissive or active displays. How it works: The basic structure of an OLED display consists of an emissive layer placed between a cathode (which injects electrons) and an anode (which removes electrons). Electricity enters through the cathode layer, passes into the emissive layer and conductive layer to create light, then out through the anode layer. Uses: OLED display technology can be used in foldable smartphones, rollable TVs, as backlighting in LCD TVs, for gaming, and inside VR headsets. Positives: OLED displays deliver excellent picture quality, wide viewing angles, infinite contrast, fast response rate, and brilliant colors with true blacks. They are energy efficient, simpler to make, and much thinner than LCDs. OLED panels can be built to be flexible and even rollable. Negatives: OLED displays are sensitive to light and moisture. Blue LEDs degrade faster than other LED colors causing color distortion over time. They are also prone to image retention and burn-in. Active Matrix Organic Light Emitting Diode (AMOLED) Active Matrix Organic Light Emitting Diode (AMOLED) and Super AMOLED are recent technologies used in smartphone displays. How it works: AMOLED displays are a type of OLED panel that uses active matrix technology. Active-matrix displays have active capacitors arranged in a matrix with thin film transistors (TFTs). This technology enables the control of each individual pixel for rapid state changes, including changing brightness and color. AMOLEDs have touchscreen functions integrated into the screen. Uses: AMOLED and Super AMOLED panels are used in high-end mobile devices, flat screen monitors, curved screens, and touchscreens. Positives: AMOLED displays offer a high picture quality and fast response time. Color and brightness are consistent across the screen. Fast-moving images and motion are displayed clearly without blurring or ghosting. Super AMOLED panels can display a wider range of colors with enhanced contrast, which makes them easy to view in a wider variety of lighting conditions. Negatives: AMOLED displays have the same problems as OLED displays (listed above) plus AMOLED panels can be difficult and expensive to manufacture. Inorganic mini-LEDs (mLEDs) Inorganic mini-LEDs (mLEDs) are a next-generation, emissive display technology. How it works: Mini-LED displays work the same way that OLED displays work, but the individual LED size is much smaller at approximately 50-60 micrometers. Uses: Mini-LED displays are used for LCD backlighting in smartphones, public information displays, signage, electronics, vehicle displays, and more. Mini-LEDs are also the tech behind “Liquid Retina XDR” screens. Positives: Mini-LED displays offer ultra high luminance, superior HDR fineness, long lifetimes, thin panels, and are readable in sunlight. They are also less expensive than micro-LED displays. Wolcott | 15  Negatives: Mini-LED displays, when used as LCD backlighting, are limited by the properties of LCD technology. Mini-LED displays for mobile devices are more expensive than OLED displays. Inorganic micro-LEDs (μLEDs) Micro-LEDs (μLEDs) are also emissive, next-generation displays. How it works: Micro-LED displays work the same way that OLED displays work, but the individual LED size is extremely small at 15 micrometers. Uses: Micro-LED displays can be used in smartphones, AR/VR headsets, wearables, public information displays, wall-sized TVs, vehicle displays, and more. Positives: Micro-LED displays offer superior performances across virtually all common display features, such as brightness, reaction speeds, power consumption, durability, color gamut, stability, viewing angles, HDR, contrast, refresh rates, transparency, seamless connectivity, and more. Micro-LED displays are readable in sunlight and have sensor integration capability. Negatives: Micro-LED displays are expensive to manufacture and are not yet ready for mass production. Key takeaways The two main technologies used in mobile displays are Liquid Crystal Display (LCD) and Organic Light Emitting Diodes (OLED). Each technology has its own benefits and drawbacks when used in mobile device displays, among other consumer goods. Common LCDs include: ○ In-Plane Switching (IPS) displays ○ Twisted Nematic (TN) displays ○ VA-Vertical Alignment displays Common and upcoming OLED displays include: ○ Active Matrix Organic Light Emitting Diode (AMOLED) displays ○ Inorganic mini-LEDs (mLEDs) displays ○ Inorganic micro-LEDs (μLEDs) displays What is a cyclical redundancy check? Ethernet is a data link level protocol How the fuck do we prevent the electrical currents representing our 1s and 0s from crashing into each other? It’s a li’l thing called CSMA/CD. Boot Methods While the most common way to boot a computer is to simply push the power button and allow the normal process to run, there are many other boot options. This reading covers the various methods you can use to boot a computer. Internal method You can create partitions on the computer’s drive so that only one part of the drive runs the boot process. A common reason to partition your drive is to have two separate operating systems on your computer, such as both Windows and Linux. When you have two operating systems on your drive, you must choose which one will run the boot process. Having two possible systems to boot into is called dual booting. Wolcott | 16 While having two operating systems can be helpful for various reasons, it is especially helpful when one system is failing or unable to boot. If this happens, you can still boot the computer using the other system and troubleshoot from there. External tools External tools can be used to boot the computer. You can load the needed resources on an external tool to boot a system before any problems happen. External bootable devices include: USB drive: You use a USB drive loaded with resources needed to boot the computer. This drive is inserted into a USB port and chosen at startup. Optical Media: You use a disk loaded with booting resources. This disk can be a DVD, CD, or Blu-ray disk and is loaded through the computer's optical drive. Solid State Boot Drive: You use a solid state drive to boot. Solid state drives do not use spinning discs or moving parts. This solid state drive can be installed in your computer or can be a smaller device such as a flash drive. External hot-swappable drive: You boot from an external hard drive that can be moved between computers without turning it off. Network boot: You boot the operating system directly from a local area network (LAN) without using a storage device. Your computer must be connected to a LAN for this option. Internet-based boot: You boot the computer from an internet source, as long as it is a secure source. Your computer must be connected to the internet for this option. Window OS or Linux OS In order to boot either Windows OS or Linux OS with an external tool, you’ll need to enter BIOS at startup by pressing F2/F12/Del keys. From there you can change the boot order so that the first option is the external tool you want to use. macOS If booting macOS, press and hold the Option key at startup. This will open up the Startup Manager, which will scan your computer and identify bootable devices. Then you can choose the bootable device you want to use. Key Takeaways There are multiple ways to boot a computer. A computer can be partitioned into different operating systems and you can select which OS to use when booting. You can boot from an external tool. External tools include USB drives, optical media, solid state boot drives, external hot-swappable drives, network booting, and internet-based booting. Choosing a boot method on startup varies depending on which operating system you use. Ethernet Frame Pictured RIght → Boot Methods Best Practices Wolcott | 17 The most common way to boot a computer is to simply push the power button and allow the normal startup process to run. But what happens if the normal startup process becomes corrupted and the computer will not boot? Or maybe you would like to run a computer on a different operating system than the one specified by your normal boot process. For situations like these, you have several options for booting your operating system. This reading covers the various methods you can use to boot a computer. The boot process When your computer is powered on, the BIOS/UEFI (BIOS) runs a series of diagnostic tests to make sure that the computer is in proper working order. The BIOS is a low-level software that initializes a computer's hardware to make sure everything is good to go. A boot device is selected based on a boot order that is configured in the BIOS. Devices that are attached to your system, like hard drives, USB drives, and CD drives are checked in this configured boot order and the computer searches these devices for a small program called a “bootloader.” Once your computer finds a bootloader on a device, it executes this program. The bootloader program then initiates a process that loads the specific operating system setup that you want to use. You can choose a computer’s boot method by telling the BIOS on which device to search for the bootloader. If you want to run an OS setup that’s stored on a USB drive, you can configure the boot order in your computer’s BIOS to search for a bootloader on a USB drive first. Configuring boot options Boot order is the order in which a computer chooses which boot files to use to startup. The boot order determines your boot method. To set the boot order for a computer, you need to enter the BIOS and configure the boot options. To enter your computer’s BIOS on a Windows or Linux computer, power on the system and look for an on-screen message that says which function key you should press to enter setup. The function keys used for entering the BIOS vary between computer manufacturers and the version of BIOS. Some of the more common function key messages are "Press DEL to enter SETUP," "F2=SETUP," or "Press F12 to enter SETUP." If booting macOS, press and hold the Option key at startup. This will open up the Startup Manager, which will scan your computer and identify bootable devices. Then you can choose the bootable device you want to use. If you press the specified function key during the Windows or Linux power up process (before the OS begins to load), you will open your BIOS program. A BIOS screen will look similar to this: The BIOS screen will vary depending on your computer manufacturer and BIOS version, but all BIOS programs will feature a Boot Options menu. The Boot Options menu is where you can set your preferred boot method. The boot options menu lists all the devices attached to your system where it may find a bootloader program. These include devices like internal hard drives, USB drives, CD drives, as well as other storage options, like network storage or cloud storage. In the BIOS boot options menu you can set the specific order you want to search these devices for the bootloader that will load your OS setup. The BIOS will run the first bootloader that it finds. Boot method options You may find the following boot methods listed in your BIOS boot options: Wolcott | 18 External options USB drive: You use a USB drive loaded with resources needed to boot the computer. This drive is inserted into a USB port and chosen at startup. Optical Media: You use an optical media disk loaded with booting resources. This disk can be a DVD, CD, or Blu-ray disk and is loaded through the computer's optical drive. The USB drive and optical media methods are useful for recovering a computer with a corrupted OS. They can also be used to start up a computer with a different OS. For example, you might boot a Windows computer in a Linux environment by using a USB with Linux OS. You will need to prepare these media with a bootable OS in order to use them as a boot method (see resources linked below). Solid State Boot Drive: You can use a solid state drive to boot your computer. Solid state drives do not use spinning discs or moving parts. This solid state drive can be installed in the computer or can be a smaller device such as a flash drive. External hot-swappable drive: You may boot from an external hard drive that can be moved between computers without turning it off. Network boot: You can boot an operating system directly from a local area network (LAN) without using a storage device. Your computer must be connected to a LAN for this option. The network boot is used when the computer does not have an OS installed, among other things. To boot from a network, you will need to set up the Preboot Execution Environment (PXE) capability on the BIOS and have the network environment prepared for this type of request (see resources linked below). Internet-based boot: You boot the computer from an internet source, as long as it is a secure source. If you are in charge of a network and your server is down for any reason, you can use this boot method to remotely power on the server and restart network operations. Internet-based boot can be achieved in one of two ways: 1. Remote access. Remote Access Controller (IPMI or similar) has to be enabled on the BIOS and the computer needs to have a Remote access control device, such as IDRAC (see resources linked below). 2. Wake on LAN (WoL). This process requires the WoL option enabled on the BIOS (see resources linked below). The WoL instruction should come from a device in the network or use a WoL gateway, and the network card should have WoL capability. Internal options Disk partitions: You can create partitions on your computer’s drive so that only one part of the drive runs the boot process. A common reason to partition your drive is to have two separate operating systems on your computer. For example, you could have Windows on one partition of your drive and Linux on the other. When you have two operating systems on your drive, you must choose which one will run the boot process. Having two possible systems to boot into is called dual booting. While having two operating systems can be helpful for various reasons, it is especially helpful when one system is failing or unable to boot. If this happens, you can still boot the computer using the other system and troubleshoot from there. Key Takeaways There are multiple ways to boot a computer. A computer can be partitioned into different operating systems and you can select which OS to use when booting. You can boot from an external tool. External tools include USB drives, optical media, solid state boot drives, external hot-swappable drives, network booting, and internet-based booting. Choosing a boot method on startup varies depending on which operating system you use. The hierarchy of an operating system pictured left. The Kernel Space is what the OS is handling in the background. Wolcott | 19 Windows 10 and 11 Feature Matrix Windows 10 and 11 are two operating systems IT Professionals work with. This reading describes the differences between them and highlights features that are important to IT. Windows 11 was released more recently and has higher system requirements than Windows 10. Professionals will still work with Windows 10 often, as many companies still use it. The primary difference between the two operating systems is aesthetic. Windows 11’s design is more minimal, corners have been rounded, and colors are pastel. Another difference is in Windows 10, the start menu and taskbar are in the bottom left corner. In Windows 11, the start menu and taskbar are centered along the bottom. Features Apps: In Windows 10, apps can only be added from the Windows Store or installed manually. In Windows 11, Android apps can also be added natively. Virtual desktop: In Windows 10 it is possible to use Virtual Desktops, but it is unintuitive to set up. In Windows 11, the support for virtual desktops is more user-friendly making it easy to set up different desktops for work and personal use. Teams: In Windows 10, Teams is included in the operating system, but defaults to Skype for video conferencing. In Windows 11, Teams is featured prominently and incorporated into the taskbar and no longer defaults to Skype for video conferencing. Widgets: In Windows 10, there are desktop gadgets similar to widgets that can be added to the start menu. In Windows 11, widgets can be accessed from the taskbar directly. Touch and pen: Windows 11 has added more features for touch and pen use on supported devices, including vibration features for pens. Random Access Memory (RAM) Support Limitations: In Windows 10, the lowest RAM (Random Access Memory) requirements are 1GB for 32-bit versions and 2GB for 64-bit versions. In Windows 11, the base requirement is 4GB of RAM. Services and settings Domain access: Joining a domain, a centrally administered group of computers, functions the same in Windows 10 and 11. A user can quickly join a domain from the “System Properties” window. Workgroup access: Joining a workgroup, a group of computers on the same Local Area Network (LAN) with shared access and responsibilities, also functions the same in Windows 10 and 11. A user can quickly join a workgroup from the “System Properties” window. Group Policy Settings (Gpedit.msc): Editing Group Policies (with Gpedit.msc) locally or using Active Directory is largely unchanged. Note that Gpedit.msc is not available in Home licenses of Windows. Remote Desktop Protocol: The Remote Desktop tool, used for connecting to the desktop of a different computer over a network connection, is largely unchanged between Windows versions. Note that to use a Remote Desktop Server, the server machine needs to be running at least the Pro edition of Windows. Bitlocker: Bitlocker, a drive encryption tool included with Windows, is largely unchanged. Note that Bitlocker is only available for Pro and Enterprise licenses of Windows. Key takeaways Operating systems like Windows 10 and Windows 11 are constantly changing and evolving. As an IT professional, you may be required to maintain two or more versions of an operating system at the same time. IT professionals need to stay on top of changes and new development to ensure they can support their users. Wolcott | 20  Windows 10 and Windows 11 primary difference is aesthetic. Windows 11 updated and added new features to make it simpler to access or use apps services, and settings. Chrome OS is based on Linux BASH is the name of the shell (command line interface) for Linux. On windows it’s Powershell/ Command Prompt. On Mac it’s the Mac Terminal If you're having a problem with network connectivity, you will need to work your way up the "network stack” (See the 7-layer pic below) URL = Uniform Resource Locator Common Scripting Solutions In this reading, you will learn about a variety of scripting languages, their uses, and their risks. As an IT Support professional, you may need to automate routine tasks. For example, you might want to automate a backup of company data that runs every night. You might also need to automate high volume tasks, like changing security access settings on thousands of files. Scripting is a common tool used for automation. This tool can help IT Support staff save time and resources in a busy enterprise work environment. Scripting languages There are many scripting languages available to use for a variety of tasks in different operating system environments. Most scripts are written in command line environments. Scripting languages for Windows environments: PowerShell (.ps1) - Windows PowerShell is among the most common command line scripting tools used in Windows environments. PowerShell is built on the.NET platform and employs many of the same elements that programming languages do. PowerShell scripts are used for building, testing, and deploying solutions, in addition to automating system management. Batch scripts (.bat) - Batch scripts, also called batch files, have been around since the early days of MS DOS and OS/2. Batch files can execute simple tasks, like calling a set of programs to run when a computer boots up. This type of script could be useful in setting up employees’ workspaces when they power on their computers. Visual Basic Script (.vbs) - Visual Basic Script is an older scripting language. It has reached its end of life for Microsoft support and has been replaced by PowerShell scripts. However, as an IT professional, you may encounter.vbs scripts on some legacy systems. Scripting languages for Linux and Unix environments: Shell script (.sh) - Shell scripting languages, like Bash, are used in Unix or Linux environments. The scripts are often used to manipulate files, including changing file security settings, creating, copying, editing, renaming and deleting files. They can also be used to execute programs, print, navigate the operating system, and much more. The scripts run in command-line interpreter (CLI) shells, such as the Bourne shell, Bourne Again SHell (Bash), C shell, and Korn (KSH) shell. Programming languages that can be used for scripting: Wolcott | 21  JavaScript (.js) - JavaScript the most used programming language in the world. It is a lightweight language that is used for scripting in web development, mobile and web apps, games, and more. It can also be used to develop software and automate web server functions. Python (.py) - Python is a user-friendly programming language that can perform advanced tasks and import modules from libraries specially designed for automation scripts. Scripting uses - finding the right tool for the job Basic automation: Python is an excellent script for automation. It’s one of the most commonly used, with many available automation libraries. Restarting machines: Many power users use PowerShell (.ps1) scripts to restart machines (Windows). For Linux machines, they can use.sh (shell) scripts. Mapping network drives: In the past, mapping network drives was accomplished with.bat or.vbs scripts. However, PowerShell scripts are most commonly used to map drives in Windows environments today. For Linux users, shell scripts can be used for this purpose. Installing applications: Batch files and shell scripts are often used for automated software installation. Automated Backups: Windows PowerShell and Linux/Unix shell scripts can automate backups. Gathering of information and data: Python is a popular choice for gathering data. Python has many available libraries to help with this task. Initiating Updates: Powershell and shell scripts can be used for initiating updates in Windows and Linux, respectively. Security risks of using scripts IT Support professionals need to be very careful when using scripts, especially with prewritten scripts copied or downloaded from the internet. Some of the security risks of using scripts could include: Unintentionally introducing malware: As an IT Support professional that is new to scripting, you may try to search the internet for assistance in writing scripts. In your search, you might find a script online for a task that you want to automate. It’s tempting to save time and effort by downloading the script and deploying it in your network environment. However, this is dangerous because scripts authored by an unverified source could potentially contain malware. Malicious scripts could have the power to delete files, corrupt data and software, steal confidential information, disable systems, and even bring down an entire network. Malicious scripts can create security weaknesses for the purpose of creating entry points for cybercriminals to penetrate networks. Scripts could also introduce ransomware attacks, which often works by encrypting file systems and then selling the decryption keys for ransom. Inadvertently changing system settings: Scripts are powerful tools for changing system settings. Using the wrong script can cause the user to inadvertently configure harmful settings. For example, one minor typo in a shell script that sets file permission security in Linux could make confidential files accessible to the world. Browser or system crashes due to mishandling of resources: Mishandling resources can lead to program crashes in the browser or cause the entire computer to crash. For example, directing too much memory to the browser can overload the computer system. Key takeaways A basic knowledge of scripting is an important tool for IT professionals. You may need to improve workflow efficiency by automating basic functions with a scripting language. Some common scripting languages include: Windows environments: batch scripts (.bat), Powershell (.ps1), Visual Basic Script (.vbs) Linux/Unix environments: shell scripts (.sh) Most OS environments: javascript (.js), Python (.py) Wolcott | 22 Scripts have multiple helpful uses, such as: Basic Automation Restarting Machines Remapping Network Drives Installing Applications Automating Backups Gathering of information/ data Initiating Updates There are risks in using scripts, including: Unintentionally introducing malware Inadvertently changing system settings Browser or system crashes due to mishandling of resources When troubleshooting or checking logs, be mindful that one error can cause “cascading errors” like a waterfall. So, go to the first error message you see, then try to fix THAT before going to the ones lower in the log. When there's multiple options to address an issue, always start with the quickest one Technical Interview Prep No filler text. Stick to what’s relevant for the job. An Elevator Pitch is a short summary of who you are, and what kind of career you’re looking for. Ex: Hi! I’m Ellis, I’ve been working at X Company as an IT Support Specialist for the past two years. During those years, I’ve learned a lot about operating systems and networking and I’m looking to switch to a system administrator position, where I can focus on large scale deployments. Hi! I’m Jamie, I’m in my senior year at Springfield University, studying Computer Science. I enjoy being able to help people and solve problems, so I’m looking forward to putting my tech skills into practice by working as an IT Support Specialist after I graduate. My name is Rob Clifton, and I’m a Program Manager at Google. I manage all of our hiring efforts for our junior IT support roles. I’ve interviewed hundreds of candidates, and I help train our interviewers on how to find the best talent in the industry. Technical Interview Tips: 1. Having a strong problem-solving strategy is more important than having all the answers! 2. Active Listening Skills: a. Make eye contact b. Nod to show understanding c. Ask follow-up questions 3. Remember to slow down IT Best Practices: Start with the quickest step first Follow the cookie crumbs (start where the problem occurred and work from there (like start at the first instance of an error message in a log) It’s important to prioritize right when managing the IT of a company. ○ Time-sensitive issues Wolcott | 23 Course #2: The Bits and Bytes of Computer Networking An IP points only to a network, and a MAC Address points to a device/ host. An IP Address is a 32-bit number, aka 4 octets, aka a number between 1 and 232 (4,294,967,296) BUT it ain’t as simple as between 1 and 232 because of IP classes. Class A is the biggest which can have an 8-bit network id (like a number between 1 and 256) and a host id of 24 bits. TCP/IP Five-Layer Network Protocol Transmission Control Protocol/ Internet Protocol Copper & Fiber are the two main materials for network cables. Cables The physical layer consists of devices and means of transmitting bits across computer networks. Wolcott | 24  Crossover cables are used to connect two computing devices directly to one another. As an IT Support specialist, you might use a short crossover cable to connect an IT administrator laptop directly to an Enterprise machine (e.g., server, switch, router, hub, etc.). This type of connection is normally used to update, repair, and perform other administrative tasks on the Enterprise machine. Cabling Tools: You can use a crimper to connect wires Wifi Analyzer measures wifi power and stability Use a toner probe to “find ethernet and internet connectors” Use a punch down tool to “connect wires to panels and jacks” The loopback plug “tests ports” You can use a network tap to copy traffic information that can be used to monitor devices. A cable stripper removes the protective coating from wires You can use a cable tester to measure integrity for standards compliance. Encapsulation: An Ethernet frame, is usually limited in size to 1,518 bytes Address classes give us a way to break the total global IP space into discrete networks. Wolcott | 25 An IP address has 4 octets (1.2.3.4). No number should ever exceed 255 because an octet in binary is 28 and thus can’t count past 255 (including 0). Let's explore what you can discover by running a real IP address through an IP Lookup website like this one. There are a handful of practical reasons people use IP Lookup, even with its limitations: Law enforcement and fraud investigators use online tools to see what ISP is hosting a spammer. Blacklist databases use it to find spammers or other violators and block their access to email servers. Retailers often use IP Lookup to make sure someone charging thousands of dollars is at the mailing address linked to the card...and not actually overseas with a stolen credit account. You can use it to verify that someone who tells you in an email that they're across town isn't really in an abandoned warehouse in another country. A Subnet ID is how to break a big network into chunks. Instead of your IP being made up of a network and host ID, it’s a network, subnet, then host ID. A subnet mask is a bunch of 1s that define what to ignore when identifying a host address. The 0s in a subnet mask distinguish the bits reserved for a host address. Picture below: Classless Inter-Domain Routing (CIDR) (Above right) This figure talks about how many hosts you can get with different CIDR configurations. Whereas the Address Classes for IPs could only give you a network of 254, 65 thousand or 16 million hosts, CIDR allows networks to simply remove a 1 from the subnet mask to allow for twice as many potential hosts. Note that there are almost always 2 hosts that are meant to be unused when designing a network. So instead of building the max 256 hosts on a class C network, you’d realistically only be able to have 254. ARP = Address Resolution Protocol Basic Routing Tables have 4 columns Wolcott | 26 https://www.coursera.org/learn/computer-networking/lecture/BVuUA/routing-tables (Definitions here ^^^) Destination Network Next Hop Total Hops Interface Dissection of a TCP Segment (below) The SYN and ACK are control flags that establish a connection before data transfer. (Above) ← In TCP the server is constantly acknowledging that it’s about to receive some data. The four-way handshake is how computers close the connection, though it technically is possible to continue transfer in simplex form if one computer sends a FIN flag that isn’t reciprocated. Non-routable IP Addresses: 10.0. 0.0/8 ( Range: 10.0. 0.0 – 10.255. 255.255 ) – Available IPs: 16,777,214. 172.16. 0.0/12 ( Range: 172.16. 0.0 – 172.31. 255.255 ) – Available IPs: 1,048,574. 192.168. 0.0/16 ( Range: 192.168. 0.0 – 192.168. 255.255 ) – Available IPs: 65,534. Socket States Client-side Both-sides Server-side Wolcott | 27  LISTEN SYN_SENT SYN_RECEIVED ESTABLISHED FIN_WAIT CLOSE_WAIT CLOSED System Ports versus Ephemeral Ports Network services are run by listening to specific ports for incoming data requests. A port is a 16-bit number used to direct traffic to a service running on a networked computer. A "service" (or "server") is a program waiting to be asked for data. A "client" is another program that requests this data from the other end of a network connection. This reading explains how the Transmission Control Protocol (TCP) uses ports and sockets to establish a network connection and deliver data between services and clients. System Ports stay the same (ports 1-1023) and identify a specific thing. Ephemeral Ports are temporary. (ports 49152 through 65535) They can change numbers, turn on and off, etc. The ones in between those ports are User Ports TCP ports and sockets Ports are used in the Transport Layer of the TCP/IP Five-Layer Network Model. At this layer, the TCP is used to establish a network connection and deliver data. A TCP "segment" is the code that specifies ports used to establish a network connection. It does this on the service side of the connection by telling a specific service to listen for data requests coming into a specific port. Once a TPC segment tells a service to listen for requests through a port, that listening port becomes a "socket." In other words, a socket is an active port used by a service. Once a socket is activated, a client can send and receive data through it. Three categories of ports Since a 16-bit number identifies ports, there can be 65,535 of them. Given the number of ports available, they have been divided into three categories by the Internet Assigned Numbers Authority (IANA): System Ports, User Ports, and Ephemeral Ports. System Ports are identified as ports 1 through 1023. System ports are reserved for common applications like FTP (port 21) and Telnet over TLS/SSL (port 992). Many still are not assigned. Note: Modern operating systems do not use system ports for outbound traffic. User Ports are identified as ports 1024 through 49151. Vendors register user ports for their specific server applications. The IANA has officially registered some but not all of them. Ephemeral Ports (Dynamic or Private Ports) are identified as ports 49152 through 65535. Ephemeral ports are used as temporary ports for private transfers. Only clients use ephemeral ports. Not all operating systems follow the port recommendations of the IANA, but the IANA registry of assigned port numbers is the most reliable for determining how a specific port is being used. You can access the IANA Service Name and Transport Protocol Port Number Registry here or check out this helpful list of commonly used ports. Wolcott | 28 How TCP is used to ensure data integrity The TCP segment that specifies which ports are connected for a network data transfer also carries other information about the data being transferred (along with the requested data). Specifically, the TCP protocol sends acknowledgments between the service and client to show that sent data was received. Then, it uses checksum verification to confirm that the received data matches what was sent. Port security Ports allow services to send data to your computer but can also send malware into a client program. Malicious actors might also use port scanning to search for open and unsecure ports or to find weak points in your network security. To protect your network, you should use a firewall to secure your ports and only open sockets as needed. Key takeaways Network services are run by listening to specific ports for incoming data requests. Ports are represented by a single 16-bit number (65535 different port ids) Ports are split up by the IANA (Internet Assigned Numbers Authority) into three categories: System Ports (ports 1-1023), User Ports (ports 1024-49151), and Ephemeral (Dynamic) Ports (ports 59152-65535). A socket is a port that a TCP segment has activated to listen for data requests. Ports allow services to send data to your computer but can also send malware into a client program. It's important to secure your ports. The most common Web Servers are Microsoft IIS, Apache, and nginx. While there are bajillions of different applications that can operate on the “Application Layer,” different applications need to use their respective standardized protocol (like HTML for web browsers & servers) if they want to interact with other instances of the application. the IP address, subnet mask, and gateway for a host must be specifically configured, a DNS server, is the fourth and final part of the standard modern network configuration. These are almost always the four things that must be configured for a host to operate on a network in an expected way. Port Forwarding seems like an amazing security measure to completely masquerade the IP of something like a web server which would automatically receive all traffic with a destination port of 80 or 443. Non-routable Address space is space that will NEVER get traffic from the internet. Therefore, if your router has NAT set up, you can use one single IP address for all your internet traffic and then let up to thousands of hosts within your network to use non-routable address space with no problem! A very clever way to take advantage of the remaining of the 4.2 billion possible IPv4 addresses Wolcott | 29 USENET was invented by Duke Graduate Students to transmit info across phone lines for computers. Broadband Protocols Broadband communications require a set of instructions, rules, and communication to various network layer protocols to support operation. Point to Point Protocol (PPP) for broadband communications is a set of instructions used to transmit data between two directly connected devices. This reading will cover the definitions, structures, and details of Point to Point Protocol (PPP) and Point to Point Protocol over Ethernet (PPPoE). Point to Point Protocol (PPP) Point to Protocol (PPP) is a byte-oriented protocol broadly used for high-traffic data transmissions. PPP functions at the data link layer, which transmits data between two devices on the same network. PPP is designed to link devices, so the endpoints do not need to be the same vendor to work. Configuring PPP When configuring PPP for the devices on your network, you have the following options: Multilink connection provides a method for spreading traffic across multiple distinct PPP connections. Compression increases throughput by reducing the amount of data in the frame. Authentication occurs when connected devices exchange authentication messages using one of two methods: ○ Password Authentication Protocol (PAP) is a password authentication option that is hard to obtain plaintext from if passwords are compromised. ○ Challenge Handshake Authentication Protocol (CHAP) is a three-way handshake authentication that periodically confirms the identity of the clients. Error detection includes Frame Check Sequence (FCS) and looped link detection. ○ Frame Check Sequence (FCS) is a number included in the frame calculated over the Address, Control, Protocol, Information, and Padding fields used to determine if there has been data loss during transmission. ○ Looped link detection in PPP detects looped links using magic numbers. A magic number is generated randomly at each end of the connection, so when a looped message is received, the device checks the magic number against its own. If the line is looped, the number will match the sender's magic number, and the frame is discarded. Sub-protocols for PPP In addition, two sub-protocols for PPP occur on the network layer when the network decides what physical path the information will take. These protocols use the configuration options you set for the endpoints. Network Control Protocol (NCP) will be used to negotiate optional configuration parameters and facilities for the network layer. There is an NCP for each higher layer protocol used by the PPP. Link Control Protocol (LCP) initiates and terminates connections automatically for hosts. It automatically configures the interfaces at each end like magic numbers and selecting for optional authentication. Data is sent using PPP in a frame. A frame is a collection of data sent to a receiving point. PPP uses the following frame format: Wolcott | 30  Flag is a single byte and lets the receiver know this is the beginning of the frame. Depending on the encapsulation, there may or may not be a start flag or an end flag. Address is a single byte, and it contains the broadcast address. Control is a single byte required for various purposes but also allows a connectionless data link. Protocol varies from one to three bytes which identify the network protocol of the datagram. Data is where the information you need to transmit is stored and has a limit of 1500 bytes per frame. Frame check sequence (FCS) is 2 or 4 bytes and is used to verify data is intact upon receipt at the endpoint. When the data is packaged in a frame, it undergoes encapsulation. Encapsulation Encapsulation is the process by which each layer takes data from the previous layer and adds headers and trailers for the next layer to interpret. These frames are sent to the other endpoint where the process is reversed, which is called De-encapsulation. PPP can get expensive and hard to manage due to all the direct cables and links required. In this case, you may want to switch to a multi-access Ethernet solution. Point to Point Protocol over Ethernet is a protocol made to bridge the gap between directly connected endpoints and other devices. Point to Point Protocol over Ethernet (PPPoE) Point to Point protocol over Ethernet (PPPoE) is a way of encapsulating PPP frames inside an ethernet frame. PPPoE is a solution for tunneling packets over the DSL connection service provider's IP network and from there to the rest of the Internet. Like PPP, PPPoE provides authentication, encryption, and compression, though it primarily uses Password Authentication Protocol (PAP) for authentication. A common use case is PPPoE using DSL services where a PPPoE modem-router connects to the DSL service or when a PPPoE DSL modem is connected to a PPPoE-only router using an Ethernet cable. PPP is strictly point-to-point, so frames can only go to the intended destination. PPPoE requires a new step because ethernet connections are multi-access enabled (every node connects to another). This requires an additional step called the discovery stage. The discovery stage establishes a session ID to identify the hardware address. This stage ensures data gets routed to the correct place. PPPoE is an encapsulation of PPP inside an ethernet frame. PPPoE retains the same architecture, configuration options, and frame data as PPP but with one extra layer of ethernet encapsulation. Key takeaways Broadband internet requires several protocols to make sure different connected devices can communicate with each other. Point to Point Protocol (PPP) encapsulates data, so any PPP configured devices can communicate without issue. Point to Point over Ethernet (PPPoE) is an extra layer of encapsulation for standard PPP frames, to enable data to be sent over ethernet connections. Wan Protocols V2 Wolcott | 31 In this reading, you will continue learning about the various components of Wide Area Networks (WANs). WAN configurations are important for IT Support professionals to understand when working with the geographically dispersed networks of large organizations. WANs can be connected through the Internet with connections provided by Internet Service Providers (ISPs) in each locale. Regional WANs can also be formed by connecting multiple Local Area Network (LAN) sites using equipment and cables leased from a regional ISP. Security for WANs across the public Internet can be configured through Virtual Private Networks (VPNs). Physical versus software-based WANs WAN router: Hardware devices that act as intermediate systems to route data amongst the LAN member groups of a WAN (also called WAN endpoints) using a private connection. WAN routers may also be called border routers or edge routers. These routers facilitate an organization’s access to a carrier network. WAN routers have a digital modem interface for the WAN, which works at the OSI link layer, and an Ethernet interface for the LAN. Software-Defined WAN (SD-WAN): Software developed to address the unique needs of cloud-based WAN environments. SD-WANs can be used alone or in conjunction with a traditional WAN. SD-WANs simplify how WANs are implemented, managed, and maintained. An organization’s overall cost to operate a cloud-based SD-WAN is significantly less than the overall cost of equipping and maintaining a traditional WAN. One of the ways that SD-WANs help reduce operational costs is by replacing the need for expensive lines leased from an ISP by linking regional LANs together to build a WAN. WAN optimization There are multiple techniques available to optimize network traffic and data storage on a WAN: Compression: Reducing file sizes to improve network traffic efficiency. There are many compression algorithms available for text, image, video, etc. The sender and the receiver will need apps that offer the same compression/decompression algorithm to encode and decode the compressed files. Deduplication: Prevents files from being stored multiple times within a network to avoid wasting expensive hard drive space. One copy of the file is kept in a central location. All other “copies” are actually file pointers to the single copy of the file. This saves valuable hard drive space, makes performing data backups more efficient, and reduces the amount of time needed to recover from data loss disasters. Protocol Optimization: Improves the efficiency of networking protocols for applications that need higher bandwidth and low latency. Local Caching: Storing local copies of network and internet files on a user’s computer to reduce the need to resend the same information across the network every time the file i