This section of the Cyber Ninja Training Plan is a course that explains the material for the first half of the CompTIA A+ certification exam.

There is plenty of good material available for the exam, but Professor Messer offers high-quality training, freely available.

Check the CompTIA A+ page to make sure the newest version of the A+ exam matches with the videos by Professor Messer. CompTIA exams are usually every three years, and the most recent A+ exam came out in April 2022.

It took me about two weeks to get through the videos, then I took another week to do practice tests. I found a study bundle published by Sybex for about $90 CAD, which includes a bunch of practice tests. Moving forward, I’ll take a day to test myself after I complete each study section.

My Notes

Section 0: How to Pass the A+ Exams

  • Computer Technology Industry Association (CompTIA)
  • Vendor-neutral
  • Core 1
    • Mobile Devices
    • Networking
    • Hardware
    • Virtualization and Cloud Computing
    • Hardware and Network Troubleshooting
  • Core 2
    • OS
    • Security
    • Software Troubleshooting
    • Operating Procedures
  • 3.5 years, roughly, so check the CompTIA website
  • Multiple choice and performance-based
  • Follow the exam objectives
  • Watch the videos
  • Get a good book
  • Get as much hands-on as possible
  • Test yourself often
  • Exam objectives. Seriously

Section 1.0: Mobile Devices

1.1 - Laptop Hardware

  • Keycaps and the mechanics underneath are very delicate.
  • SO-DIMM - Small Outline Dual In-line Memory Module
    • Often used for laptops and mobile devices
  • Others are soldered to the system board
  • Laptop storage
    • 2.5 form factor
    • Magnetic disk, SSD, or M.2
  • HDD to SSD is an impressive upgrade, like a getting a new laptop
  • Can also clone to HDD (i.e., make an image)
    • Need software like CloneZilla
  • 802.11 wireless and Bluetooth
    • Mini PCI and Mini PCI Express
  • Biometrics
    • Fingerprint or face recognition
      • Something you are
    • Requires hardware and software
      • See Sign-in options in Windows
    • Relatively secure
  • Near-field communication (NFC)
    • 4cm or less
    • Data transfers or authentication
    • Don’t need a password

      1.2 - Laptop Displays

  • Liquid crystal display (LCD)
    • Lightweight
    • Low power
    • Inexpensive
    • Black levels are a challenge
    • Requires separate backlight
  • TN (Twisted Nematic) LCD
    • Fast response times
    • Poor viewing angles - color shifts
  • IPS (In Plane Switching) LCD
    • Excellent color
    • More expensive than TN
  • VA (vertical Alignment) LCD
    • Good compromise between
  • Organic Light Emitting Diode (OLED)
    • Very thin, no glass needed
    • No backlight
    • Higher cost than LCD
  • Wi-Fi antennas
    • WiFi main and aux
    • Bluetooth
    • Antenna wires wrap around the laptop screen
  • Webcam
    • Video capture
    • Both video and audio
    • Not good for casual use
  • CCFL - Cold Cathode Fluorescent Lamp
    • Higher voltage
    • Added thickness
    • No longer common, used on older laptops
  • The latest laptops use LED-backlit LCD displays
  • Digitizer
    • Use a pen-like device as input
      • Stylus
  • Touchscreen
    • Merge laptop and tablet input
    • Digitizer responds to touch

1.3 - Connecting Mobile Devices

  • Universal Serial Bus
    • Micro B
    • Mini B
    • Type A
  • USB-C
    • 24-pin double-sided
    • Can transmit other signals
      • DP
      • HDMI
      • Thunderbolt
  • Lightning
    • Apple 8-pin
    • High power output
  • Serial interfaces
    • DB-9
      • Aka DE-9
      • For RS-232 signals
      • Use a USB to DB-9 converter
  • NFC
    • Send small amounts of data
    • Built into your phone
    • Access token, identification ‘card’
  • Bluetooth
    • High speed comms over short distances
  • Hotspot
    • Turn your phone into a WiFi hotspot
    • Extend your cell data network to all your devices
    • Dependent on phone type

1.3 - Mobile Device Accessories

  • Touch pens
    • Stylus / touchscreen pen
    • Handwriting
    • Precise selection
  • Active stylus
    • Digital stylus
    • More advanced
    • Communicates directly to the device
    • Programmable buttons
    • Must be compatible with the tablet
  • Drawing pad
    • Use an active stylus with an external digitizer
    • Very precise input
    • Third-party device
  • Trackpad
    • Replace the mouse
      • Useful in tight working areas
    • External options
    • Drag and tap, or multiple finger input options
    • Enable and disable
  • Headsets
    • Earphones and microphone
    • Wired or Bluetooth
  • Speakers
    • Mobile audio
  • Camera / webcam
    • Internal or external
    • Accessible from many apps
  • Docking station
    • Use external keyboard and mouse
    • Extend interfaces
    • Add functionality
    • Avoid cable issues
  • Port replicator
    • Similar to docking station
    • Connects through USB

1.4 - Cellular Standards

  • 2G
    • GSM
    • CDMA
    • Poor data support
  • GSM
    • Global System for Mobile Communications
    • 90% of the market
    • Used multiplexing
  • CDMA
    • Code Division Multiple Access
      • Each call uses a different code
    • Not much adoption elsewhere
  • 3G technology
    • Introduced in 1988
    • Several megabits per second
    • Bandwidth improvement
      • GPS
  • 4G and LTE
    • Long Term Evolution
    • Converged standard (GSM and CDMA providers)
    • Based on GSM and EDGE (Enhanced Data Rates for GSM Evolution)
    • 150 Mbit/s
  • 5G
    • 2020
    • Higher freqs
    • 10 Gbit/s
    • Significant IoT impact
  • Updates
    • PRL updates
      • Preferred Roaming List
    • Allows your phone to connect to the right tower
  • Hotspot
    • Your own personal wireless router

1.4 - Mobile Device Connectivity

  • Bluetooth pairing
    • Use or verify a PIN
    • Pair the devices one time
    • Check with the manufacturer
    • Enable Bluetooth on both devices
    • Set to discoverable mode
    • Select discovered device
    • Enter or confirm PIN
    • Test connectivity
  • GPS
    • Created by US DoD
    • Over 30 sat’s in orbit
    • Precise navigation
    • Need at least 4 satellites
    • Determines location based on timing differences
    • Phones can also use WiFi and cell towers
  • MDM (Mobile Device Management)
    • Manage company-owned or BYODs
    • Centralized management of the mobile devices
    • Set policies on apps, data, camera, etc.
    • Manage access control
      • Force screen locks and PINs
    • Corporate email configuration
      • User doesn’t need to configure anything
    • Two-factor authentication
      • Biometrics, auth app, etc.
    • Control apps
      • Allow or restrict

1.4 - Mobile Device Configuration

  • Configuring a mobile device
    • Preconfigured
      • Telephone and text
    • Email
      • Configurations vary
    • Data synchronization
  • Microsoft 365
    • Outlook, Exchange
    • Authenticate to 365
      • Username, password
    • Same process for Google Workspace
  • iCloud
    • iOS and iPadOS
    • Select sync options
    • Sync to macOS
  • Syncing data
    • Mail
    • Pictures, etc.
    • Data caps and transfer costs
      • Cell or 802.11 networks

Section 2.0: Networking

2.1 - Introduction to IP

  • A series of moving vans
    • Efficiently move large amounts of data
      • Use a shipping truck
    • The network topology is the road
      • Ethernet, DSL, cable system
    • The truck is the IP Internet Protocol
    • The boxes hold your data
    • Inside the boxes are more things
      • Application information
  • TCP and UDP
    • Transported inside the IP
      • Encapsulated by the IP
    • Two wayts to move data
    • OSI Layer 4
      • Transport layer
    • Multiplexing
      • Use many different applications at the same time
      • TCP and UDP
  • TCP
    • Connection-oriented
      • A formal connection setup and close
    • Reliable delivery
      • Recovery from errors
      • Can manage out-of-order messages or retransmissions
    • Flow control
      • The receiver can manage how much data is sent
  • UDP - User Datagram Protocol
    • No formal open or close the connection
    • Simple transaction
    • Unreliable
      • No error recovery
      • No reordering of data
    • No flow control
  • Why would you ever use UDP?
    • Real-time communication
      • Quick, doesn’t stop for your network
    • Connectionless protocols
      • DHCP Dynamic Host Config
      • TFTP Trivial File Transfer Protocol
    • It’s up to the application to track and decide what to do
  • Communication with TCP
    • Return receipt
      • HTTPS
      • SSH
    • The application doesn’t worry about out of order frames or missing data
  • Speedy delivery
    • The IP delivery truck delivers from one IP address to another IP address
    • Boxes arrive at the house / IP address
      • Where do the boxes go?
      • Each box has a room name
    • Port is written on the outside of the box
      • Drop the box into the right room
  • Lots of ports
    • IPv4 sockets
      • Server IP address, protocol, server app port number
      • Client IP address, protocol, client port number
    • Non-ephemeral ports - permanent port numbers
      • Ports 0 through 1,023
      • Usually on a server or service
    • Ephemeral ports - temporary port numbers
      • Ports 1,023 through 65,535
      • Determined in real-time by the client
  • Port numbers
    • TCP and UDP ports can be any number between 0 and 65,535
    • Most servers use non-ephemeral
      • Not always. It’s just a number
    • Port numbers are for communication, not security
    • Service port numbers need to be ‘well known’
    • TCP port numbers aren’t the same as UDP port numbers
  • Ports on the network
    • Web server - tcp/80
    • VoIP server - udp/5004
    • Email server - tcp/143

2.1 - Common Network Ports

  • Port numbers
    • Well-known port number
      • Client and server need to match
    • Important for firewall rules
      • Port-based security
    • A bit of rote memorization
    • Make sure you know port number, protocol, and how the protocol is used
  • FTP - File Transfer Protocol
    • tcp/20 (active mode data)
    • tcp/21 (control)
    • Authenticates with a username/password
    • Full-featured functionality
  • SSH - Secure Shell
    • Encrypted comm link - tcp/22
    • Looks and acts as Telnet
  • Telnet - Telcom Network
    • tcp/23
    • login to devices remotely
    • In-the-clear communication (not encrypted)
  • SMTP - Simple Mail Transfer Protocol
    • tcp/25
    • Also used to send from a device to a mail server
    • Other protocols are used for clients to receive email
      • IMAP, POP3
  • DNS - Domain Name System
    • udp/53
    • Converts names to IP addresses
  • DHCP - Dynamic Host Config Protocol
    • Auto config of IP addresses, subnet mask, etc
      • udp/67, udp/68
    • Dynamic / pooled
    • DHCP reservation
  • HTTP and HTTPS
    • tcp/80 HTTP
    • tcp/443 HTTPS
  • POP / IMAP
    • Receive emails from an email server
    • tcp/110 POP3
    • tcp/143 IMAP4 Internet Message Access Protocol v4
  • SMB - Server Message Block
    • Protocol used by Windows
      • File sharing, printer sharing
      • Aka CIFS
    • Uses NetBIOS over TCP/IP
      • udp/137 name services
      • tcp/139 session service
    • tcp/445 direct
  • SNMP - Simple Network Management Protocol
    • Gather stats from network devices
      • Queries udp/161
      • Traps udp/162
    • v1 - original
      • In-the-clear
    • v2 - A good step ahead
    • v3 - A secure standard
  • LDAP - Lightweight Directory Access Protocol
    • tcp/389
    • Store and retrieve info in a network directory
      • Commonly used in Microsoft Active Directory
  • RDP - Remote Desktop Protocol
    • tcp/3389

2.2 - Network Devices

  • Network devices
    • All have different roles
    • Some are combined
  • Routers
    • Routes traffic between IP subnets
      • Makes forwarding decisions based on IP address
      • Routers inside of switches sometimes called ‘layer 3 switches’
    • Often connects diverse network types
      • LAN, WAN, copper, fiber
  • Switches
    • Bridging done in hardware
      • App-specific integrated circuit (ASIC)
      • Forwards traffic based on data link address
    • Many ports and features
      • The core of an enterprise network
      • May provide Power over Ethernet (PoE)
    • Multilayer switch
  • Unmanaged switch
    • Very few config options
      • Plug and play
    • Fixed configs
      • No VLANs
    • Very little integration with other devices
    • Low price point
      • Simple is less expensive
  • Managed switch
    • VLAN support
      • Interconnect with other switches via 802.1Q
    • Traffic prioritization
    • Redundancy support
      • Spanning Tree Protocol (STP)
    • Port mirroring
      • Capture packets
    • External management (SNMP)
  • Access point
    • Not a wireless router
      • A wireless router is a router and an access point in a single device
    • It’s a bridge which extends
  • Cable infrastructure
  • Patch panels
    • Combination of punch-down blocks and RJ-45 connectors
    • Runs from desks are made once
    • Patch panel to switch can be easily changed
  • Firewalls
    • Filters traffic by port number
      • OSI layer 4
    • Can encrypt traffic into/out of the network
    • Can proxy traffic
      • A common security technique
    • Most firewalls can be layer 3 devices (routers)
  • Power over Ethernet (PoE)
    • One wire for both network and electricity
    • Phones, cameras, wireless access points
    • Power provided at the switch
  • PoE switch
    • Commonly marked on the switch or interfaces
  • PoE, PoE+, PoE++
    • Now part of the 802.3 standard
    • 15.4W DC power
    • PoE+
      • 25.5W
    • PoE++
      • 51W (Type 3)
      • 71.3W (Type 4)
  • Hub
    • ‘Multi-port repeater’
    • Everything is half-duplex
    • Becomes less efficient the busier the network gets
    • 10Mbit / 100Mbit
  • Cable modem
    • Broadband
      • Transmission across multiple freq’s
      • Diff traffic types
    • DOCSIS
      • Data Over Cable
    • High-speed networking
    • Multiple services
  • DSL modem
    • ADSL
      • Uses phone lines
    • Download is faster than upload
  • ONT
    • Optical network terminal
      • Fiber to the premises
    • Connect the ISP fiber network to the copper network
    • Line of responsibility
      • One side is yours
      • The other is the ISPs
  • Network Interface Card (NIC)
    • The fundamental network device
      • Every device on the network has a NIC
    • Specific to the network type
      • Ethernet, WAN, etc
    • Often built into the motherboard
    • Many options

2.2 - Software Defined Networking

  • SDN
    • Diff functional planes of operation
    • Separate into logical units
    • Infrastructure layer / Data plane
      • Forwarding, trunking, encrypting, NAT
    • Control layer / Control plane
      • Manages the actions of the data plane
      • Routing tables, session tables, NAT tables
    • Application layer / Management plane
      • Configure and manage the device
        • SSH, browser

2.3 - Wireless Network Standards

  • Wireless standards
    • 802.11 Managed by IEEE LAN/MAN
    • Many updates over time
    • The Wi-Fi trademark (Wi-Fi Alliance)
  • 802.11a
    • Original standards - 1999
    • 5GHz range
    • 54 Mbit/s
    • Smaller range than 802.11b
  • 802.11b
    • Also an original standard
    • Not an upgrade, it’s different frequencies
    • 2.4GHz
    • Better range, less absorption problems
    • Baby monitors, Bluetooth, microwave ovens operate on the same freq range
  • 802.11g
    • 2003
    • 2.4GHz range
    • 54 Mbit/s
    • Backwards-compatible
    • Same freq problems as the ‘b’
  • 802.11n (Wi-Fi 4)
    • 2009
    • 5GHz and/or 2.4GHz
    • 40MHz channels
    • 600 Mbit/s
    • Uses MIMO
  • 802.11ac (Wi-Fi 5)
    • 5GHz band
    • Less crowded
    • Denser signal modulation
    • Eight MU-MIMO streams
    • Nearly 7 Gbits/s
  • 802.11ax (Wi-Fi 6)
    • 2021
    • 5GHz or 2.4GHz
    • 1,201 megabits per second per channel
    • Eight bi-directional MU-MIMO
    • OFDMA
      • Orthogonal freq-div mult access
      • Improves high-density installations
      • Works like cell comms
  • Long-range fixed wireless
    • Wireless access point in a house with stock antennas
      • 40-50 meters
    • Wireless regulations are complex
    • Signal strength is usually regulated
  • RFID
    • It’s everywhere
      • Access badges
      • Inventory
      • Pet / animal ID
      • Anything that needs to be tracked
    • Radar technology
      • Radio energy transmitted to the tag
      • RF powers the tag, ID is transmitted back
      • Bidirectional comms
      • Some can be powered
  • NFC
    • Two-way wireless
      • Builds on RFID
    • Payment systems
      • Major credit cards
    • Bootstrap for other wireless
    • Access token, ID card

2.3 - Wireless Network Technologies

  • 802.11 technologies
    • Frequency
      • 2.4 GHz or 5 GHz
      • Sometimes both -Channnels
      • Groups of freq’s, numbered by the IEEE
      • Non-overlapping is ideal
    • Regulations
      • Most countries have them
      • Spectrum use, power output, etc.
  • Band selection and bandwidth
    • Check IEEE
    • Compare 2.4 GHz with 5 GHz
      • Plenty more 5 GHz channels available
  • Bluetooth
    • Remove the wires
      • Headsets, speakers, keyboards, etc
    • Uses the 2.4 GHz band
    • Unlicensed ISM band
    • Same as 802.11
    • Short-range
      • Roughly 10 meters

2.4 - Network Services

  • DNS server - Domain Name System - Converts names to IP addresses - Vice versa - Distributed naming system
    • Balanced across many servers
    • Critical resource
  • DHCP
    • Auto IP config
    • Very common service
      • Most home routers
    • Enterprise DHCP will be redundant
  • File server
    • Centralized storage
      • A fileshare
    • Standard system of file mgmt
      • SMB, SFP, etc.
    • Front-end hides the protocol
  • Print server
    • Connect a printer to the network
    • May be software in a computer
    • May be built-in to the printer
      • Network adapter and software
    • Uses standard printing protocols
      • SMB, IPP, LPD
  • Mail server
    • Store your incoming mail
      • Send your outgoing mail
    • Usually managed by the ISP or IT department
    • 24/7 support
  • Syslog
    • Standard for message logging
      • Diverse systems, consolidated log
    • Usually a central logging receiver
      • Integrated in the SIEM
      • Need a lot of space
  • Web server
    • Respond to browser requests
      • HTTP/HTTPS
      • HTML or HTML5
    • Web pages are stored on the server
  • Authentication server
    • Login auth to resources
      • Centralized management
    • Almost always an enterprise service
    • Usually a set of redundant servers
      • Always available
      • Extremely important
  • Spam
    • Unsolicited messages
      • Email, forums, etc
    • Various content
      • Commercial
      • Phishing
      • Selling
    • Significant technology issue
      • Security concerns, storage costs, managing the spam
  • All-in-one security appliance
    • Next-gen firewall
      • Unified Threat Management (UTM)
    • URL filter / Content inspection
    • Malware inspection
    • Spam filter
    • CSU / DSU
    • Router / Switch
    • Firewall
    • IDS / IPS
    • Bandwidth shaper
    • VPN endpoint
  • Load balancers
    • Distribute the load
      • Multiple servers
    • Large-scale implementations
      • Web server farms
    • Fault tolerance
      • Server outages have no effect
    • Manage load across servers
  • Proxy server
    • An intermediate server
      • Client makes the request
      • Proxy makes the request
      • Provides results back to the client
    • Useful features
      • Access control, caching, URL filtering
  • SCADA / ICS
    • Supervisory Control and Data Acquisition System
    • PC manages equipment
      • Power generation, energy, logistics
    • Distributed control systems
      • Real-time information
    • Requires extensive segmentation
  • Legacy and embedded systems
    • Legacy
      • Really old
      • May also be very important
      • Learning old things can be just as important as learning the new things
    • Embedded
      • Purpose-built
      • Not usual to have direct access to the operating system
      • Alarm system, door security, time card system
  • IoT (Internet of Things)
    • Appliances
      • Fridges
    • Smart devices
      • Speakers
    • Air control
      • Thermostats, etc
    • Access
      • Smart doorbells
    • May require a segmented network
      • Limit any security breaches

2.5 - IPv4 and IPv6

  • IP addressing
    • IPv4 is the primary protocol for almost everything we do
    • IPv6 is now part of all major operating systems
      • And the backbone of our internet infrastructure
  • IPv4 addresses
    • OSI Layer 3 address
    • 32 bits - 4 bytes
    • Max decimal value for each byte is 255
  • IPv6 addresses
    • 128-bit address
    • Crazy amount of options
    • Uses hex numbers
    • DNS is very important
  • Networking with IPv4
    • IP Address
      • Every device needs a unique IP address
    • Subnet mask
      • Used by the local device to determine what subnet it’s on
        • You’ll ask for the subnet mask all the time
    • Default gateway
      • The router that allows you to communicate outside of your local subnet
  • DNS servers
    • We remember names
    • Internet routers don’t know names
      • Routers only know IP addresses
    • Something has to translate between names and IP addresses
      • DNS does it
    • You configure two DNS servers
      • That’s how important it is

2.5 - Assigning IP Addresses

  • DHCP
    • IPv4 addess config used to be manual
    • 1993 - bootstrap protocol BOOTP
      • Didn’t auto assign everything
    • DCHP does it automatically
  • DHCP process
    • DORA
      • A four-step process
        • Discover
          • Find a DHCP server
        • Offer
          • Get an offer
        • Request
          • Lock in the offer
        • Acknowledge
          • DHCP server confirmation
  • Turning dynamic into static
    • DHCP assigns an IP from the first available
      • Your IP will occasionally change
    • You may not want your IP to change
    • Disable DHCP on the device
      • Configure the IP info manually
      • Requires additional admin
    • Better Configure an IP reservation on the DHCP server
      • Associate a specific MAC address with an IP address
  • Avoid manual configs
    • No DHCP server reservation
    • Difficult to change later
    • A DHCP reservation is preferable
  • Automatic Private IP Addressing (APIPA)
    • A link-local address
    • IETF has reserved 169.254.0.0 through 169.254.255.255
    • Automatically assigned

2.6 - DNS Configuration

  • Domain Name System
    • Translates human-readable names into IP
    • Hierarchical
      • Follow the path
    • Distributed database
      • 13 root server cluster (Over 1,000 actual servers)
      • Over 275 country codes
  • DNS hierarchy
  • DNS lookup
    • use the dig command, or nslookup
  • DNS records
    • Resource Records (RR)
      • The database records of domain name services
    • Over 30 record types
      • IP addresses, certs, etc
    • These are important and critical configurations
      • Backup, test, check your settings
  • DNS config
    • Written in text, simple
    • Could also be a web-based GUI
  • Address records (A) (AAAA)
    • Defines the IP of a host
    • A records are for IPv4
    • AAAA records are for IPv6
  • Mail exchange record (MX)
    • Determines the host name for the mail server
      • Not an IP; it’s a name
  • Text records (TXT)
    • Human-readable text info
      • Useful public info
    • Can be used for verification purposes
    • Commonly used for email security
  • Viewing TXT records with dig
    • dig professormesser.com txt
  • Sender Policy Framework (SPF)
    • A list of all servers authorized to send email for this domain
    • Prevent mail spoofing
  • Adding an SPF TXT record
  • Domain Keys Identified Mail (DKIM)
    • Digitally sign a domain’s outgoing mail
  • DMARC
    • Domain-based Message Authentication, Reporting, and Conformance
    • Prevent unauthorized email use
    • An extension of SPF and DKIM
    • Extra step of telling it what to do with the emails that don’t validate through SPF or DKIM

2.6 - DHCP Configuration

  • Scope properties
    • IP address range
      • And excluded addresses
    • Subnet mask
    • Lease durations
    • Other scope options
      • DNS server
      • Default gateway
      • VOIP servers
  • DHCP pools
    • Grouping of IPs
      • Each subnet has its own scope
      • 192.168.1.9/24
    • A scope is generally a single contiguous pool of IPs
  • SOHO DHCP server
  • DHCP address assignment
    • Dynamic assignment
      • Has a big pool of addresses to give out
    • Automatic assignment
      • DHCP keeps a list of past assignments
      • You’ll always get the same IP address
  • DHCP address allocation
    • Address reservation
    • Table of MAC address
      • Each MAC address has a matching IP address
    • Other names
  • DHCP leases
    • Leasing your address
      • It’s only temporary
      • But can seem permanent
    • Allocation
      • Assigned a lease time by the DHCP server
    • Reallocation
      • Reboot your computer
      • Confirms the lease
    • Workstation can also manually release the IP address
  • DHCP renewal
    • T1 timer
      • 50% of the lease time by default
    • T2 timer
      • 87.5% of the lease time
      • If the original DHCP server is down, try rebinding with any DHCP server
  • The DHCP lease process

2.6 - VLANs and VPNs

  • LANs
    • Local Area Networks
      • Same broadcast domain
  • Virtual LANs
    • A group of devices in the same broadcast domain
    • Separated logically instead of physically
  • Configuring VLANs
  • VPNs
    • Encrypted (private) data traversing a public network
    • Concentrator
      • Encryption / decryption access device
      • Often integrated into a firewall
    • Many deployment options
      • Specialized hardware
      • Software options available
    • Used with client software
  • Client-to-site VPN
    • On-demand access from a remote device
      • Software connects to a VPN concentrator
    • Some software can be configured as always-on

2.7 - Internet Connection Types

  • Satellite networking
    • Comms to a sat
      • Non-terrestrial comms
    • High cost relative to terrestrial networking
      • 50 Mbit/s down
      • Remote sites, difficult-to-network sites
    • High latency
      • 250 ms up, 250 ms down
      • Starlink advertises 40 ms and it working on 20 ms
    • High frequencies - 2 GHz
      • Line of sight, rain fade
  • Fiber
    • High speed data comms
      • Freq’s of light
    • Higher install costs than copper
      • Equip is more costly
      • Long distance
    • Large installation in the WAN core
      • Supports very high data rates
    • Slowly approaching the premises
  • Cable broadband
    • Broadband
      • Transmission across multiple freqs
      • Different traffic types
    • Data on the ‘cable’ network
      • DOCSIS
    • High-speed
      • Up to 1 GBit/s
  • DSL
    • ADSL
      • Uses telephone lines
    • 200 MBit/s down / 20 MBit/s up
    • Depends how far you are from the central office
  • Cellular networks
    • Mobile devices
      • Cell phones
    • Separate land into cells
    • Tethering
      • Turn your phone into a wireless router
    • Mobile hotspot
      • Standalone devices
      • Use your phone for other things
  • Wireless Internet Service Provider (WISP)
    • Connect rural or remote locations
      • Internet access for everyone
    • Many diff deployment techs
    • Need an outdoor antenna
      • 10 - 1,000 MBit/s

2.7 - Network Types

  • LAN
    • Local is relative
    • A bulding or a group of buildings
    • Ethernet and 802.11 wireless
  • WAN
    • Spanning the globe
    • Generally connects LANs across a distance
      • Much slower
    • Many diff WAN techs
  • PAN
    • Personal Area Network
      • Bluetooth
    • Automobile
      • Audio output
      • Integrate with phone
    • Mobile phone
      • Wireless headset
    • Health
      • Workout telemetry, daily reports
  • MAN
    • Metropolitan Area Network
      • A network in your city
      • Larger than a LAN, smaller than a WAN
    • Historically MAN-specific topologies
      • Metro Ethernet
    • Common to see government ownership
      • They ‘own’ the right-of-way
  • SAN
    • Storage Area Network
      • Looks and feels like a local storage device
      • Block-level access
      • Very efficient reading and writing
    • Requires a lot of bandwidth
      • May use an isolated network and high-speed network techs
  • WLAN
    • Wireless LAN
      • 802.11 techs
    • Mobility
      • Within a building
    • Expand coverage with additional access points

2.8 - Network Tools

  • Cable crimpers
    • ‘Pinch’ the connector onto a wire
      • Coaxial, twisted pair, fiber
    • Connect the modular connector to the Ethernet cable
      • The final step
    • Metal prongs are pushed through the insulation
  • Crimping best-practices
    • Get a good crimper
      • And a good pair of electrician’s scissors / cable snips
      • And a good wire stripper
    • Make sure you use the correct modular connectors
      • Difference between wire types
    • Practice, practice, practice
  • Wifi analyzer
    • Wireless networks are incredibly easy to monitor
      • Everyone ‘hears’ everything
    • Purpose-built hardware or mobile device
    • Identify errors and interference
      • Validate antenna location and installation
  • Tone generator
    • Toner probe
      • Where does that wire go?
      • Follow the tone
    • Tone generator
      • Puts an analog sound on the wire
    • Inductive probe
      • Doesn’t need to touch the copper
      • Hear through a small speaker
  • Using the tone generator and probe
    • Easy wire tracing
    • Connect the tone generator to the wire
    • Use the probe to locate the sound
      • It’s easy to find
  • Punch-down tool
    • Punch a wire into a wiring block
    • Can be tedious
    • Trims the wires during the punch
  • Punch-down best-practices
    • Organization is key
    • Maintain your twists
    • Document everything
  • Cable testers
    • Relatively simple
      • Continuity test
      • A simple wire map
    • Can identify missing pins
      • Or crossed wires
    • Not usually used for frequency testing
      • Crosstalk, signal loss, etc.
  • Loopback plugs
    • Useful for testing physical ports
      • Or fooling your applications
    • Serial / RS-232
    • Network connections
      • Ethernet, T1, Fiber
    • Not a cross-over cable
  • Taps and port mirrors
    • Intercept network traffic
      • Send a copy to a packet capture device
    • Physical taps
      • Disconnect the link, put a tap in the middle
      • Can be active or passive
    • Port mirror
      • Port re-direction, SPAN
      • Software-based tap
      • Can work well in a pinch, but has limited functionality

Section 3.0: Hardware

3.1 - Network Cables

  • The importance of cable
    • Fundamental
  • Usually only get one good shot
  • Everything has to plug in somewhere
  • Balanced pair operation
    • Two wires with equal and opposite signals
    • Transmit+, Transmit- / Receive+, Receive-
    • The twist is the secret!
      • Keeps a single wire constantly moving away from the interference
    • Pairs in the same cable have a different twist rates
  • Copper cable categories
    • Cat 5 - 100 meters
    • Cat 5e (enhanced) - 100 meters
    • Cat 6 - Unshielded: 55 meters; Shielded: 100 meters
    • Cat 6A (augmented) - 100 meters
  • Coaxial cables
    • Two or more forms share a common axis
    • RG-6 used in television/digital cable
  • Direct burial STP

3.1 - Optical Fiber

  • Fiber comms
    • Transmission by light
      • The visible spectrum
    • No RF signal
      • Very difficult to monitor or tap
    • Signal slow to degrade
      • Transmission over long distances
    • Immune to radio interference
      • There’s no RF
  • Multimode fiber
    • Short-range comms
      • Up to 2 km
    • Relatively inexpensive light source
      • i.e., LED
  • Single-mode fiber
    • Long-range comms
      • Up to 100 km without processing
    • Expensive light source
      • Commonly uses lasers

3.1 - 568A and 568B Colors

  • ISO / IEC 11801 cabling standards
  • TIA 568 standard

3.1 - Peripheral Cables

  • USB
    • Simplify connections
      • Printers, keyboards, etc.
    • USB 1.1
      • Low speed: 1.5 megabits per second, 5 meters
      • Full speed: 12 MBit/s, 5 meters
    • USB 2.0
      • 480 megabits per second, 5 meters
    • USB 3.0
      • Superspeed
      • 5 gigabits per second, ~3 meters
  • USB connectors
  • USB-C
    • Lots of different
    • Replaces them all
    • Describes the connector itself, not the signal
  • Versions and naming
    • Standard doesn’t change, just the names
  • Thunderbolt v3
    • Max 3 meters
    • 40 Gbit/s

3.1 - Video Cables

  • VGA (Video Graphics Array)
    • DB-15 connector
    • Blue color
    • Video only (no audio)
    • Analog signal, no digital
  • HDMI
    • Video and audio stream
      • All digital, no analog
      • ~ 20 meter distance
    • 19-pin (Type A) connector
  • DisplayPort
    • Digital info sent in packet form
      • Like ethernet and PICe
    • Compatible with HDMI and DVI
      • DP > HDMI
  • DVI (Digital Visual Interface)
    • Single and dual link video
      • Single: 3.7 Gbps
      • Dual: 7.4 Gbps
      • No audio support
    • DVI-A
      • Analog signals
    • DVI-D
      • Digital
    • DVI-I
      • Integrated

3.1 - SATA Device Cables

  • SATA (Serial AT Attachment)
    • SATA Revision 1.0
      • SATA 1.5 Gbps
    • Rev 2.0 3 Gbps
    • Rev 3.0 6Gbps
    • Rev 3.2 16 Gbps
  • Separated into power cable and data cable
  • eSATA
    • External version
    • Looks similar, but it’s definitely different

3.1 - SCSI Device Cables

  • Small Computer Systems Interface
  • Up to 16 devices in a SCSI ‘chain’
  • Many diff formats
  • Advantages
    • Not just for hard drives
      • Scanners, CD-ROM drives
    • Many devices on a single bus
    • Very intelligent form of connectivity
    • Industry longevity

3.1 - PATA Device Cables

  • Parallel AT Attachment
  • Originally called Integrated Drive Electronics (IDE)
  • Speeds improved over the years, but it’s old
  • Now called PATA

3.1 - Adapters and Converters

  • The best laid plans…
    • Need an adapter
  • Convert between different connectors
  • Convert from one format to another
    • You need Ethernet but you only have USB
  • A good temp or permanent fix
  • DVI-D and HDMI are electrically compatible
    • No loss of video quality
  • DVI to VGA
    • Analog signals
    • Only 640 x 480 is officially supported
    • For digital, you’ll need a converter
  • USB to Ethernet
    • Some laptops don’e have a wire Ethernet interface
      • Convert USB to Ethernet
    • USB-C to USB-A
      • Use your older peripherals
  • USB hub
    • Connect many devices
      • High speed USB connectivity

3.1 - Copper Connectors

  • RJ11 connector
    • 6 position, 2 conductor
    • Telephone or DSL connection
  • RJ45
    • 8 position, 8 conductor
      • Modular connector
      • Ethernet
  • F-connector
    • Cable television
      • Cable modem
      • DOCSIS
  • Punchdown block
    • Wire-to-wire patch panel
    • Wires are ‘punched’ into the block
  • USB-C
    • Interface the same, signal can vary
  • Molex connector
    • Power connectore
      • Provides +12V and +5V
    • Power for many devices in the computer case
  • Lightning
    • 8-pin digital signals
    • Higher output power for phones and tablets
  • DB-9
    • Letter refers to the connector size
    • Commonly used for RS-232 signals

3.1 - Fiber Connectors

  • LC - Local Connector
  • ST - Straight Tip
  • SC - Subscriber Connector
    • Square connector

3.2 - Memory

  • What is memory? Random Access Memory is the most common
  • RAM is not referring to hard drive or SSD
  • Data and programs can only be used when moved to RAM
  • RAM slots
    • Standardized
    • One of the most important components of your computer
    • Every motherboard is different
  • DIMM
    • Dual inline memory module
    • Electrical contacts are different on each side
    • 64 bit data width
  • SO-DIMM
    • Small Outline Dual In-Line Memory Module
      • About half the width as a DIMM
    • Used in laptops and mobile devices
  • Dynamic Random Access Memory
    • The memory on the DIMM
    • Dynamic
      • Needs contant refreshing
      • Without refreshing, the data in memory disappears
    • Random access
      • Any storage location can be accessed directly
      • Not like magnetic tape
  • SDRAM
    • Synchronous DRAM
    • SDRAM is synchronous with the common clock system
      • Queue up one process while waiting for another
  • Double Data Rate 3 (DDR3) SDRAM
    • Twice the data rate of DDR2
      • Max 16 GB per DIMM
    • No backwards compatibility
  • DDR4
    • Speed increases
      • Max 64 GB per DIMM
  • DDR5
    • Max 64 GB
    • Faster data transfers between module and motherboard

3.2 - Memory Technologies

  • Virtual memory
    • Different names
      • Virtual RAM, swap file, etc.
    • Swap currently unused application data to storage
      • Free up space for other applications
    • Managed automatically by the operating system
  • Multi-channel memory
    • Dual-channel, triple-channel, or quad
    • Memory combos should match
      • Exact matches are best
    • Often coloured differently
  • Memory that checks itself
    • Used on critical systems
      • VM servers, database servers, any server
    • Parity memory
      • Adds an additional parity bit
      • Won’t always detect and can’t correct
    • Error Correcting Code (ECC)
      • Detects and corrects errors on the fly

3.3 - Storage Devices

  • Hard disk drives (HDD)
    • Non-volative magnetic storage
      • Rapidly rotating platters
    • Random-access
      • Retrieve data from any part of the drive at any time
    • Moving parts
      • Spinning platters, moving actuator arms
      • Limits the speed and components can also break
  • SSD
    • Non-volatile memory
      • No moving parts
    • Very fast performance
      • No spinning drive delays
  • 2.5” SATA interface
  • mSATA (Mini-SATA)
    • Shrink the SATA drive into smaller devices
    • Smaller than 2.5” SATA drives
    • Quickly replaces by M.2 standard
  • AHCI vs NVMe
    • SATA was desinged for hard drives
      • Uses AHCI (Advanced Host Controller Interface)
      • SATA revision 4 throughput up to 600 MB/s
      • SSDs need a faster comms method
  • NVMe (Non-Volatile Memory Express)
    • Designed for SSD speeds
    • Lower latency, supports higher throughputs
    • Take advantage of NVMe with an M.2 interface
  • M.2 interface
    • Smaller form factor
      • No SATA or power cables
    • Can use a PCI Express bus connection
      • 4 GB/s throughput or faster when using a NVMe PCIe x4
    • Different connector types
      • Needs to be compatible with the slot key
  • B-key and M-key
    • M.2 doesn’t guarantee NVMe
      • Your interface may be using AHCI
      • Check your documentation
  • Flash drives
    • Flash memory
      • EEPROM (Electrically erasable programmable read-only memory)
      • Non-volatile memory
      • No power required to retain data
    • Limited number of writes
      • Can still read the data
    • Not designed for archival storage
  • Optical drives
    • Small bumps read with a laser beam
    • Relatively slow
    • Many different formats
      • CDs, DVD, Blu-ray

3.3 - RAID

  • Data redundancy
    • Hard drives can store huge amounts of data
    • Hard drives fail
    • What to do?
    • RAID is not backup!
  • RAID
    • Redundant Array of Independent Disks
      • They’re also inexpensive disks
    • Diff RAID levels
      • Some redundant, some not
  • RAID 0 - Striping
    • File blocks are split between two or more physical drives
    • High performance
    • No redundancy
      • A drive failure breaks it
  • RAID 1 - Mirroring
    • File blocks are duplicated between two or more physical drives
    • High disk utilization
    • Duplicate drives
    • High redundancy
  • RAID 5 - Striping with parity
    • File blocks are striped
      • Along with a parity block
      • Requires at least three disks
    • Efficient use of disk space
      • Files aren’t duplicated, but space is still used for parity
    • High redundancy
      • Data is available after drive failure
  • RAID 10 (1+0) - A stripe of mirrors
    • The speed of striping, the redundancy of mirroring
      • The best of both worlds
    • Need at least 4 drives

3.4 - Motherboards - Form Factors

  • Form factors
    • Physical size
    • Basic layout
      • Room for small changes
    • Power
      • Standard connectors
    • Airflow
      • Increasingly important
    • Wikipedia - over 40 different types
  • Given a scenario
    • Focus on which motherboard would be the best choice
    • Media center, thin client, etc.
  • Standard-ATX
    • Advanced Technology Extended
    • Started in 1995
    • Power
      • 20 or 24 pin
  • Mini-ITX
    • Low-power
    • 2001
    • Fits almost any enclosure
    • Same screw sizes as ATX
    • Single-purpose computing, e.g. streaming

3.4 - Motherboard Expansion Slots

  • Computer bus
    • Comms path
      • A city of technology
    • Internal PC growth
      • Indie pathways
    • System expansion
      • Additional capabilities
  • Conventional PCI
    • Peripheral Component Interconnect
    • 1994
    • Many expansion options
      • 32-bit or 64-bit
  • PCI Express
    • Aka PCIe
      • Replaces older standard
    • Communicates serially
      • Unidirectional serial ‘lanes’
    • More lanes means more data transfer

3.4 - Motherboard Connectors

  • 24-pin power
    • Main power
      • 3.3, 5 or 12V
    • 20 pin was replaced by 24
  • 4-pin ATX
    • Additional 12V power for older motherboards
  • Headers
    • Many uses
      • Power
      • Lights
      • Buttons

3.4 - Motherboard Compatibility

  • Intel and AMD
    • Two solid choices
    • Cost
      • AMD tends to be a bit cheaper
    • Different sockets
      • Your locked in because it’s designed for a particular CPU
    • Choosing a side
      • AMD is value and Intel is performance
      • But that’s changing all the time
  • Server motherboards
    • Multisocket
      • Supports multiple CPUs
    • Memory slots
    • Expansion slots
    • Overall size usually rack-mounted
  • Desktops
    • Can range from full-size to compact
    • Single CPU
    • Memory slots
    • Expansion slots
  • Mobile motherboards
    • Laptops
      • Small and light
    • CPUS
      • Limited in speed
    • Limited system modification
    • Portability
      • Small, low-power
  • System board in laptops
    • Propriety
      • Built to fit
    • Replacement isn’t easy
      • Swap the entire board

3.4 - The BIOS

  • Basic Input / Output System
    • The software used to start your computer
      • Firmware
      • System BIOS
      • ROM or flash memory
    • Initializes CPU and memory
    • POST - power on self test
    • Look for a boot loader
  • Legacy BIOS
    • Been around for 25 years
    • Limited hardware support
  • UEFI BIOS
    • Unified Extensible Firmware Interface
    • A defined standard
    • Designed to replaced the legacy BIOS

3.4 - BIOS Settings

  • The secret buttons
    • Del, F1, F2, Ctrl-S
    • Hyper-V
    • VMWare Workstation Player
    • Not VirtualBox
    • UEFI BIOS simulator
  • Fast startup
    • Starts so quickly you can’t open the BIOS
    • From Windows desktop
      • Hold shift when cliking Restart
  • Important tips
    • Make a backup of the BIOS config
      • Write detailed notes
      • Take a picture
    • Don’t make a change unless you’re certain of the setting
    • Did I mention the backup?
  • Boot options
    • What happens when you power on?
    • Disable hardware
      • Unavailable to the operating system
    • Modify the boot order
      • Which boots first?
      • USB, SSD, or hard drive
  • USB permissions
    • A security challenge
      • Very small storage devices
      • Very large capacities
    • USB connections
      • Convenient
      • High speed
    • US DoD banned flash media for 15 months in 2008 SillyFDC worm
  • Fans
    • Computing creates heat
      • A lot of heat
    • Many cooling fans
      • CPU
      • Chassis
    • Motherboard often include an integrated fan controller
  • Secure Boot
    • Malicious software can own your system
      • Malicious drivers or OS
    • Secure boot
      • Part of UEFI
    • Digitally sign known-good software
      • Crypto secure
    • Supported in many operating systems
  • UEFI BIOS Secure Boot
    • Protections
      • Public key
      • Checked during BIOS update
      • Prevents unauthorized writes to the flash
    • Verifies the bootloader
  • Boot password management
    • BIOS / User password
      • System won’t start
      • Needed to start OS
    • Supervisor password
      • Restrict BIOS changes
    • Remember your password!
      • Must reset BIOS to recover
  • Clearing a boot password
    • Store the BIOS config
    • CMOS
      • A type of memory
      • May be backed up
    • Usually flash memory these days
    • Reset with a jumper
      • Short two pins on the motherboard
  • The CMOS battery
    • Not needed for today’s flash-based storage
      • May only be needed to maintain date/time
    • On older systems you can reset the BIOS by removing the battery
  • Trusted Platform Module (TPM)
    • A specification for cryptographic functions
      • Hardware to help with encryption functions
    • Random number generator, etc.
    • Persistent memory
    • Versatile memory
    • Password protected
  • Hardware Security Module (HSM)
    • Large environments
    • High-end crypto hardware
    • Key backup
    • Crypto accelerators

3.4 - CPU Features

  • Operating system tech
    • 32-bit vs 64-bit
      • Processor specific
    • 4 GB vs 17 billion GB
  • Hardware drivers are specific to the OS version
    • 32-bit OS cannot run 64-bit apps
    • But 64-bit can run 32-bit apps
  • Advanced RISC Machine (ARM)
    • CPU designed by Arm Ltd.
    • Simplified instruction set
      • Less power
      • Less heat
    • Lines are constantly blurring
  • Processor cores
    • Dual/Quad/Octa/Multi-core
      • And more all the time
    • Multiple cores
      • Each core has its own cache
  • Multithreading
    • Hyper-Threading Technology (HTT)
    • One CPU, acts like two
    • Doesn’t actually work as fast as two
      • 15-30%
    • OS must be written for HTT
  • Virtualization support
    • Run other OS’s within a single hardware platform
    • Resource-intensive
    • Added to the processor
    • Intel VT
    • AMD-V

3.4 - Expansion Cards

  • Expansion cards
    • Extend the functionality of your computer
    • Relatively simple process
    • Install hardware
      • Add a card
    • Install a driver
  • Sound card
    • High-end output
    • Advanced headphone amp
    • Home theater
    • Inputs, music capture, podcasting, microphone
  • Video card
    • Many CPUs include an integrated GPU
    • Discrete graphics
    • High-performance
  • Capture card
    • Video as input
      • Video capture
      • Live streaming
      • External cameras
    • High performance
      • PCI Express connection
  • Network Interface Card (NIC)
    • Ethernet connection
      • Motherboard may not include a NIC
    • Additional connections
      • Servers
      • Routers
  • Documentation
    • Check the motherboard docs
      • Number and type of slots
    • Check the adapter card docs
    • May need to install drivers before
  • Driver installation
    • You checked the docs, right?
    • Check the web for the latest version
    • Uninstall previous drivers through Device Manager
    • Manufacturer provided setup program
    • Manual installation through WDM
    • Check the status in WDM

3.4 - Cooling

  • Case fans
    • Cool air is pulled through a PC
    • Always check for good airflow
    • Motherboard layout becomes important
    • Component location is key
    • Many different sizes and styles
  • On-board fans
    • Designed to cool an entire adapter card
    • Can be bulky
    • Usually on high-end graphics cards
  • Fan specs
    • Standards
      • 80 mm, 120 mm
  • Fanless
    • No noise
    • Functions are very controlled
    • Low-power components
  • Heat sink
    • Don’t touch!
  • Thermal paste
    • Place between heat sink and component
      • Moves heat away from the component
    • A little bit goes a long way
  • Thermal pad
    • Conduct heat without the mess
      • Cut to size and install
    • Easy to use
      • Won’t leak or damage
    • Almost as effective as thermal paste
    • Not reusable
  • Liquid cooling
    • Coolant through a computer
      • Not a new concept
        • Autos, mainframes
    • High-end systems
    • Gaming, graphics
    • Overclocking

3.5 - Power

WARNING - Always disconnect from the power source when working on a device - Always, seriously - Some devices store a charge in capacitors - Know how to discharge before touching - Never connect your body to any part of an electrical system - Respect electricity

  • Computer power supply
    • Computers use DC voltage
      • Most sources provide AC voltage
    • Convert 120 AC to 3.3, 5, or 12 V DC
  • Amp and volt
    • Amp: the rate of electron flow past a point in one second
      • Diameter of the hose
    • Volt: electrical pressure pushing the electrons
      • How open the faucet is
  • Power
    • Watt: measurement of real power use
    • Volts * Amps = Watts
    • 120 V * 0.5 A = 60 W
  • Current
    • Alternating current
      • Direction of current constantly reverses
      • Efficient over long distances
    • Direct current
      • Current moves in one direction with a constant voltage
  • Dual-voltage input options
    • Voltage varies by country
    • Manually switch between 120 V and 230 V
    • Don’t plug 120 V into a 230 V power source!
  • Power supply output
    • Diff voltages
    • Positive and negative voltage
      • 12 V - PCIe adapters, fans, most modern components
      • 5 V - legacy motherboards
      • 3.3 V - M.2 slots, RAM slots, logic circuits
      • 5 VSB - standby voltage
  • 24-pin motherboard power
    • Main motherboard power
    • The three main voltages
  • Redundant power supplies
    • Two or more power supplies
      • Internal to the server
    • Each power supply can handle 100% of the load
    • How-swappable
      • Replace one without powering down
  • Power supply connectors
    • Fix connectors
      • Connected to the power supply
      • Many have either too many or not enough
    • Modular
      • Add cables as needed
  • Sizing a power supply
    • Rated by watts
      • Overall and individual voltages
    • Bigger isn’t necessarily better
      • More expensive
      • Doesn’t speed up your computer
    • Physical size is standard
    • Calculate the watts required for all components
      • Many online calculators
    • Video adapters usually draw the most power
    • 50% capacity is a good rule of thumb
      • Double your calculation

3.6 - Multifunction Devices

  • MFD
    • Printer
    • Scanner
    • Fax
    • Network connection
    • Phone line
    • Print from web
  • Unboxing a device
    • These can be large
      • Make sure you have enough room
    • Check the area
  • Printer drivers
    • Specific to a printer model
      • Get it right
    • Get the right OS drivers
    • Get the right OS version
    • You can mix and match drivers
  • PCL or PostScript
    • Printer Command Language
    • PostScript
      • Popular with high-end printers
    • Make sure the drivers match the printer
  • Wired device sharing

3.7 - Printers

  • Laser printer
    • Combine a laser, high voltage, charged ions, powdered ink, heat, and paper
    • Very high quality
    • Fast
    • Very complex
  • Imaging drum
    • Image is drawn onto a photosensitive drum
    • Picks up toner
    • Can be separate from the toner cartridge
  • Fuser assembly
    • Heat and pressure
      • Melt plastic toner powder
      • Permanently bond toner to paper
  • Transfer belt and roller
    • Color laser printers
    • Four toner cartridges
    • Image is transferred from all cartridges to the belt
  • Pickup rollers
    • Pick up paper
    • Single at a time
    • Should be periodically replaced or cleaned
  • Separation pad
    • Pull just the top sheet from the paper tray
    • Small and inexpensive
  • Duplexing assembly
    • Printers usually print on a single side
    • Printing on both sides is a two step process
    • You need mechanisms to flip the page
  • Process
    • Processing
    • Charging
    • Exposing
    • Developing
    • Transferring
    • Fusing
    • Cleaning

3.7 - Laser Printer Maintenance

  • Replacing the toner
    • Look for the messages
      • Low doesn’t mean empty
    • The toner can also contain the OPC drum
      • Sensitive to light; keep it in the bag
    • Power down the printer
    • Remove packing strips and replace with new
  • Maintenance kit
    • They wear out
      • Many moving parts
      • Heat and pressure
    • Check manufacturer for maintenance kit
    • Check page counter
    • Power off and replace the components
    • Reset the page counter when you’re done
  • Cleaning
    • Dirty
      • Toner and paper dust
    • Check the maker’s recommendation
    • Outside - damp cloth
    • Inside - wipe dust away

3.7 - Inkjet Printers

  • Inkjet printers
    • Relatively inexpensive
    • Quiet
    • High-res
    • Expensive ink
      • Proprietary
    • Eventually fades
    • Clogs easily

3.7 - Inkjet Printer Maintenance

  • Cleaning print heads
    • Need to stay clear so they don’t clog
    • Can be started manually or automatically
  • Replacing inkjet cartridges
    • CMYK
    • Recycle
  • Calibration

3.7 - Thermal Printers

  • White paper
    • Turns black when heated
    • No ink!
  • Very quiet
    • Almost silent
  • Paper is sensitive to light and heat
    • And clear tape
  • Feed assembly
    • Pull paper through the printer
  • Heating element
    • Full-length heating element
      • No moving print head
  • Thermal paper
    • Paper covered with a chemical
    • Cash register, ATMs
    • Looks like normal, but feels different

3.7 - Thermal Printer Maintenance

  • Thermal paper replacement
    • Relatively inexpensive
      • But must be exact
    • Diff sizes
      • Not like laser printer paper
    • Actual replacement is easy
  • Cleaning the heating element
    • Liquid cleaner
      • Iso alcohol
      • Get a cleaning pen
    • Swab gently
    • Use a cleaning card
  • Removing debris
    • Paper and dust
    • Blow out the printer
    • Wipe it out
    • Avoid using a vacuum
  • Paper sensitivity to heat
    • Heat is used to create the output on the thermal paper
    • Avoid hot areas
    • Receipt will also fade over time

3.7 - Impact Printers

  • Dot-matrix (impact) printers
    • Print head with a small matrix of pins
    • Good for carbon / multiple copies
    • Low cost per page
    • NOISY
    • Poor graphics
    • Relatively niche
  • Moves back and forth
    • Pins hit ribbon and paper
  • Printer ribbon
    • Fabric
      • One long ribbon
      • Never ending circle
    • Easy to replace
    • Proprietary size
  • Tractor feed
    • Continuous paper feed
    • Paper pulled through with holes on the side of the paper
    • Holes have to be lined up perfectly

3.7 - Impact Printer Maintenance

  • Printer ribbon replacement
    • Single ribbon
      • One long circle
    • Replace when ink becomes too light
    • Designed to be modular
      • Replace in a minute
  • Print head replacement
    • Takes a lot of abuse
    • Gets hot
    • Another modular part
    • Replace with the ribbon for the best effect
  • Replacing paper
    • Not as easy as a laser printer
    • Forms must be positioned correctly
    • Must feed without constraint

3.7 - 3D Printers

  • 3D printers
    • Print in three dimensions
      • Create a 3D model and print it
    • Additive manufacturing
      • Build in layers
    • Rapid prototyping
    • Deploy designs anywhere in the world, or in space
  • Filament printing
    • Fused Deposition Modeling (FDM)
      • Melt filament to print 3D objects
    • Print a layer, move up, print another layer
    • Good all-around printer
      • Larger print bed than resin printers
  • Resin printing
    • SLA 3D Printing
      • Smooth and finely detailed prints
    • Resin is hardened using a light source
    • Resin must be handled properly
  • The print bed
    • A flat adhesive surface
    • Needs to be level and clean
    • Filament printing

Section 4.0: Virtualization and Cloud Computing

4.1 - Cloud Models

  • Cloud computing
    • More than just a server hosted elsewhere
      • Extend the management of apps and services
    • Deploy an infrastructure in minutes
      • Create and tear down as you need
    • International scope
      • Deploy in specific parts of the world
    • Use only the required resources
      • Cost is based on the amount of use
  • Cloud deployment models
    • Private
      • Your own data center
    • Public
      • Available to everyone over the Internet
    • Hybrid
      • A mix of both
    • Community
      • Several org’s share the same resources
  • Infrastructure as a service (IaaS)
    • Sometimes called Hardware as a Service (HaaS)
      • Outsource your equipment
    • You’re still responsible for the management
      • And for the security
    • Your data is out there, but more within your control
    • Web server providers
  • Software as a service (SaaS)
    • On-demand software
      • No local installation
      • Why manage your own email distribution? Or payroll?
    • Central management of data and apps
      • Your data is out there
    • A complete app offering
      • No dev required
      • Gmail, Microsoft 365
  • Platform as a service (PaaS)
    • No servers, no software, no maintenance team, no HVAC
      • Someone else handles the platform, you handle the dev
    • You don’t have direct control of the data, people, or infrastructure
      • Choose carefully
    • Put the building blocks together
      • SalesForce.com
  • Cloud models

4.1 - Cloud Characteristics

  • Share resources
    • Internal cloud
      • No resources are shared
      • Build your own cloud
      • Pay for everything up front
      • No ongoing costs
    • External cloud
      • Share with a public cloud
      • Costs may be metered or up-front
      • Owned by a third party
  • Metered and non-metered
    • Metered cloud services
      • Pay for what you use
      • Cost to upload / store / download
    • Non-metered
      • You pay for a block of storage
      • No cost to upload / download
  • Rapid elasticity
    • Scale up and scale down as needed
    • Seamless to everyone
  • High availability
    • Always available
    • Redundancy provides availability
  • File synchronization
    • Info can be duplicated across cloud locations
  • Desktop as a service (DaaS)
    • Basic app usage
      • Apps run on a remote server
      • Virtual Desktop Infrastructure, DaaS
      • Local device is a keyboard, mouse, and screen
    • Minimal OS on the client
    • Network connectivity
      • Big network requirement

4.2 - Client-side Virtualization

  • Virtualization
    • One computer, many OS’s
    • Separate OS, independent CPU, memory, etc.
    • Host-based virtualization
    • Standalone server that hosts virtual machines
    • Been around since 1967
  • Legacy software and operating systems
    • Need to run different app versions on the same system
    • App only runs on a previous OS version
      • Create a VM with the older OS
  • Cross-platform virtualization
    • Windows / macOS / Linux doesn’t do everything
      • Each has strength and weaknesses
    • Run at the same time
      • Don’t need to switch or reboot
    • Save time and resources
  • The hypervisor
    • Virtual Machine Manager
      • Manages the virtual platform and guest OS’s
    • May require a CPU that supports virtualization
      • Can improve performance
    • Hardware management
      • CPU
      • Networking
      • Security
  • Resource requirements
    • CPU Processor Support
      • Intel - Virtualization Technology
      • AMD - AMD-V
    • Memory
      • Above and beyond host OS requirements
    • Storage
      • Need enough for each OS image
    • Network
      • Configurable on each guest OS
      • Virtual switch
  • Security
    • VM escaping
    • Many hosted services are virtual environments
  • Guest OS security
    • Every guest is self-contained
      • Like a real computer
    • Use traditional security controls
      • Firewall, etc
    • Watch out for rogue VM’s
      • The bad guys try to install their own system
        • You’re in big trouble
    • Self-contained VMs can be dangerous
  • Network requirements
    • Most client-side VM managers have their own virtual networks
    • Shared network address
      • The VM shares the same IP as the physical host
      • Uses a private IP internally
      • Uses NAT to convert
    • Bridged network address
      • The VM is a device on the physical network
    • Private address
      • The VM does not communicate outside of the virtual network

5.0 - Hardware and Network Troubleshooting

5.1 - How to Troubleshoot

  • Change management
    • Change control
      • A formal process for managing change
      • Avoid downtime, confusion, and mistakes
      • Corporate policy and procedures
    • Nothing changes without the process
      • Plan for a change
      • Estimate risk
      • Have a recovery plan
      • Test before making the change
      • Document all of this and get approval
      • Make the change
  • Troubleshooting process
    • Identify the problem
      • Info gathering
        • Get as many details as possible
        • Duplicate if possible
      • ID symptoms
      • Question users
      • Determine if anything has changed
      • Approach multiple problems individually
      • Backup everything
    • Establish a theory
      • Start with the obvious
        • Occam’s razor applies
      • Consider everything
      • Make a list of all possible causes
      • Research the symptoms
    • Test the theory
      • Confirm the theory
      • Theory didn’t work?
        • Re-establish new theory
      • The theory worked
        • Make a plan
    • Create a plan of action
      • Build a plan
      • Refer to vendor instructions
      • ID potential effects
    • Implement the solution
      • Fix the issue
      • Escalate as necessary
    • Verify full system functionality
      • It’s not fixed until it’s really fixed
    • Document findings
      • It’s not over until you build the knowledge base
        • Don’t lose valuable knowledge
      • What action did you take?
        • What outcome did it have?
      • Consider a formal database

5.2 - Troubleshooting Common Hardware Problems

  • POST (Power On Self Test)
    • Test major system components before booting the OS
      • Main systems (CPU, CMOS, etc.)
      • Video
      • Memory
    • Failures are usually noted with beeps and/or codes
    • Don’t bother memorizing the beep codes
  • POST and boot
    • Black screen on boot
      • Listen for beeps
      • Bad video, bad RAM, bad CPU
      • BIOS config issue
    • BIOS time and setting
      • Maintained with the motherboard battery
      • Replace the battery
    • Attempts to book to incorrect device
      • Set boot order in BIOS config
      • Confirm that the startup device has a valid OS
      • Check for media in a startup device
  • Crash screens
    • Windows Stop Error (BSOD)
    • Contains important information
      • Also written to event log
    • Useful when tracking down problems
      • Sometimes more useful for manufacturer support
  • Bluescreens and spontaneous shutdowns
    • Startup and shutdown BSOD
    • Use last known good, system restore, or rollback driver
      • Try Safe Mode
    • Reseat or remove the hardware
    • Run hardware diagnostics
      • Provided by manufacturer
      • BIOS may have it too
  • The spinning ball of death
    • The macOS spinning wait cursor
      • Feedback that something is happening
    • The spin starts, but it never stops
    • Many possible reasons
      • App bug
      • Bad hardware
      • Slow paging to disk
    • Restart the computer
      • There may be details in the console logs
  • Black screen
    • Is the monitor connected?
      • We wouldn’t ask if it wasn’t a common solution
      • Check power and signal cable
    • Input selection on monitor
      • HDMI, DVI, VGA, etc.
    • Image is dim
      • Check brightness controls
    • Swap the monitor
      • Try the monitor on another computer
    • No video after Windows loads
      • Use VGA mode (F8)
  • No power
    • No power at the source
    • No power at the power supply
    • Get out your multimeter
  • Sluggish performance
    • Task Manager
      • Check for high CPU utilization and I/O
    • Windows Update
      • Latest patches and drivers
    • Disk space
      • Check for available space and defrag
    • Laptops may be using power-saving mode
      • Throttles the CPU
    • Anti-virus and anti-malware
      • Scan for bad guys
  • Overheating
    • Heat generation
      • CPUs, video adapters, memory
    • Cooling systems
      • Fans and airflow
      • Heat sinks
      • Clean and clear
    • Verify with monitoring software
      • Try HWMonitor
        • cpuid.com
  • Smoke and burning smell
    • Electrical problems
      • The smoke makes everything work
    • Always disconnect power
      • There should never be a burned odor
    • Locate bad components
      • Even after the system has cooled down
  • Intermittent shutdown
    • No warning, black screen
      • May have some details in your Event Viewer
    • Heat-related issue
      • High CPU or graphics, gaming
      • Check all fans and heat sinks
      • BIOS may show fan status and temperatures
    • Failing hardware
      • Has anything changed?
      • Check Device Manager, run diagnostics
    • Could be anything
      • Eliminate what’s working
  • App crashes
    • App stops working
      • May provide an error message
      • May just disappear
    • Check the Event Log
    • Check the Reliability Monitor
    • Reinstall the app
  • Grinding noises
    • Computers should hum, not grind
    • Rattling
      • Loose components
    • Scraping
      • Hard drive issue
    • Clicking
      • Fan problems
    • Pop
      • Blown capacitor
  • Lockups
    • System completely stops
      • Usually not much in the event log
    • Check for any activity
      • Hard drive, status lights, Ctrl-Alt-Del
    • Update drivers and software patches
    • Low resources
      • RAM, storage
    • Hardware diagnostics may be helpful
  • Continuous reboots
    • How far does the boot go before rebooting?
      • BIOS only? OS splash screen?
    • Bad driver or configuration
      • F8, boot from last known configuration
    • Try F8, Safe Mode
      • If system starts, disable auto restarts in System Properties
  • Inaccurate system date/time
    • Bad motherbaord battery
      • Often a button style battery
    • A bad battery will require a BIOS config or date/time config on every boot
    • On older systems, can reset the BIOS config by removing the battery
      • Newer computers use a jumper

5.3 - Troubleshooting Storage Devices

  • Storage failure symptoms
    • Read/write failure
    • Slow performance
      • Constant LED activity
    • Loud click noise
      • Click of death
  • Troubleshooting disk failures
    • Get a backup
      • First thing - a bad drive is bad
    • Check for loose or damaged cables
    • Check for overheating
    • Check power supply
    • Run hard drive diagnostics
  • Boot failure symptoms
    • Drive not recognized, Boot Not Found
      • Lights
      • Beeps
      • Error messages
    • Operating system not found
      • The drive is there
      • Windows is not
    • Check your cables
    • Check boot sequence in BIOS
    • For new installation, check hardware config
      • Data and power
      • SATA cables
    • Try the drive in a different computer
  • Data loss / corruption
    • Hard drives are mechanical
      • They will eventually fail
    • Repairs are difficult and expensive
    • An SSD may simply stop working
    • Data becomes unavailable or corrupted
    • ALWAYS HAVE A BACKUP
  • RAID not found
    • Missing or faulty RAID controller
    • Each RAID is different
      • Don’t start pulling drives until you check the console!
  • SMART
    • Self-Monitoring, Analysis, and Reporting Technology
      • Use third-party utilities
    • Avoid hardware failure
      • Look for warning signs
    • Schedule disk checks
      • Built-in to most drive arrays
    • Warning drives
      • Replace the drive
  • Extended read/write times
    • A lot happens when reading or writing data
    • Delays can occur anywhere along the way
    • Input/output operations per second (IOPS)
    • Useful for comparing storage devices
      • HDD: 200 IOPS
      • SSD: 1,000,000 IOPS
  • Missing drives in OS
    • OS boots normally
      • Other drives not shown
      • Check the BIOS
    • Internal drives
      • Bad drive or disconnected cable
    • External drives
    • Network shares
      • Share might not be mounted

5.4 - Troubleshooting Video and Display Issues

  • No video image
    • Is it connected?
    • Input selection
    • Image is dim
    • Swap the monitor
    • Use VGA mode (F8)
  • Image quality problems
    • Flickering, color patterns
    • Check the cable pins
    • Distorted
      • Check the OS refresh rate and resolution settings
      • Need to match the display specs
      • Check or replace cable
    • Disable hardware acceleration
  • Native resolution
    • An LCD display is fixed
      • Pixel number doesn’t change
    • Match native resolution to the video settings
  • Burn-in
    • All monitor types have this problem
    • LCDs have image sticking
      • Try to remove by displaying a white screen for a good amount of time
  • Dead pixels
    • Always black
      • Manufacturing defect
    • Not a problem you can fix
    • Clean the monitor screen with a damp cloth
    • You’ll have to replace the monitor
      • No other option
  • Flashing screen
    • Check the video cable connections
      • A loose cable will cause loss of signal
    • Replace the video cable
    • Could be the monitor
    • Confirm the display settings in the operating system
  • Incorrect color display
    • Colors may not be properly represented
    • Monitor settings
    • Driver config
    • OS config - night light setting
  • Audio issues
    • Many monitors include speakers
      • No sound, low volume
    • May have audio controls
    • Confirm audio input over HDMI, DP, of Thunderbolt
      • Check the HDMI audio output of the OS
    • May support other audio
  • Dim image
    • Monitor video settings
    • Check the OS
    • Backlight failure
      • Some or all of the light
      • May only be a section of the screen
  • LCD projector troubleshooting
    • Large screen projection
      • Conf room, large gatherings
    • Not always LCD
    • Metal-halide lamp
      • Very bright and hot
      • Expensive (~35-350 USD)
    • Always let bulbs cool
    • Intermittent shutdown
      • Cooling issue
      • Check the fans
      • Check the airflow
        • Blockages
        • Dust

5.5 - Troubleshooting Mobile Devices

  • Poor battery health
    • Replace aging battery
      • There’s only so many recharges
    • Bad reception
      • Always searching for signal
      • Airplane mode on the ground
    • Disable uncessary features
    • Check app battery usage
  • Swollen battery
    • Buildup of gas
      • Designed to self-contain
      • Do NOT open
    • Faulty battery
    • Device can be damaged
  • Broken screen
    • Time for a backup
      • Do this first
    • Replace the screen
      • No easy fixes
    • The glass is sharp
      • Screen protectors can help
      • Use clear tape until repaired
  • Improper charging
    • Check everything in the charging process
      • Cables, interfaces
    • Check the cable interface
      • Remove any obstructions
    • Check the cable
      • Don’t use frayed or damaged cables
      • Try a known-good cable
    • Verify the power adapter
      • Check with a multimeter
  • Poor or no connectivity
    • Cellular or Wi-Fi
      • Location, location, location
    • Cellular
      • Signal strength
      • Location matters
      • Outdoor connectivity may be better
    • Wi-Fi
      • Limited range
      • Interference can limit throughput
      • May need a chnnel/freq config change
  • Liquid damage
    • Many phones have a Liquid Contact Indicator
      • Turns color when liquid has been present
    • Power down the phone
      • Don’t power it back on
    • Remove the case, cards, back and battery
    • Putting the phone in a bag of rice doesn’t actually work well
      • Silica gel is better
    • Leave it alone
      • Don’t turn it on
      • Don’t charge it
      • Don’t press any keys
      • Don’t move it around
    • Wait at least a day
    • Once you’re sure, power it on and hope for the best
  • Overheating
    • Phone will automatically shut down
  • Malware
  • Cursor drift

5.6 - Troubleshooting Printers

  • Testing the printer
    • Print or scan a test page
      • Built into Windows
    • Use diagnostic tools
      • Web-based utilities built into the printer
      • Vendor specific
  • Bad output
    • Lines down the printed page
      • Inkjet: clean print heads
      • Laser: check for scratched drum
    • Faded prints, blank pages
      • Low toner or ink
    • Double / echo images
      • Laser printer drum not cleaned properly
  • Garbled print
    • Bad printer driver / wrong model
    • Verify the functionality with a test page
    • Bad application
  • Toner not sticking to the paper
    • Laser printer output smudges everywhere
  • Incorrect paper size
    • Print a letter size page
  • Paper jam
    • Careful when removing
      • Don’t rip the paper
    • Paper not feeding or misfeeds multiple pages
    • Creased paper
      • Problems in the paper path
      • Check the paper weight
  • Multiple prints pending in queue
    • Corrupted print jobs
      • Print spooler will crash
      • Mosrt spooler config will automatically restart
    • Problems are logged
      • Windows Event Viewer, Windows-PrintService
    • One job may be causing the issue
  • Incorrect color settings
    • Calibrate the monitor
      • A third-party calibration tool will help
    • Check the paper
      • Bright white
    • Calibrate the printer
      • The proper amount of ink and toner
  • Grinding noises
    • Never a good sound from your printer
    • Something is not operating properly
    • Each printer has a different process
    • May require additional maintenance
  • Finishing issues
    • Finishing happens after the ink or toner has been applied
    • Staple jams
    • Incorrect hole punch location
  • Incorrect page orientation
    • Print a portrait page
    • Check the settings when printing
    • The printer also has a default setting

5.7 - Troubleshooting Networks

  • No network connectivity
    • Do you have a link light?
      • Is it plugged in?
    • Ping loopback (127.0.0.1)
      • Is the protocol stack working?
      • Availability and intermittent connectivity
    • Ping local IP address
      • Checks local config, adapter, and link signal
    • Ping default gateway
      • Connectivity on the local network
    • Ping devices on router’s other side
      • 8.8.8.8 or 9.9.9.9
  • Intermitten wireless connectivity
    • Interference
      • Something else is using our frequency
    • Signal strength
      • Transmit signal, transmit antenna, receive antenna, etc.
    • Incorrect channel
      • Usually automatic: look for manual tuning
    • Bounce and latency
      • Multipath inteference; flat surfaces
    • Incorrect access point placement
      • Locate close to users
  • Wireless interference
    • Predictable
      • Microwave ovens
      • Cordless phones
      • High-power sources
    • Unpredictable
      • Multi-tenant building
    • Measurements
      • SNR
      • Performance Monitor
  • Signal to noise ratio
    • Signal
      • What you want
    • Noise
      • What you don’t want
    • You want a very large ratio
  • Limited or no connectivity
    • Windows alert in the system tray
    • Check the local IP address
      • An APIPA address will only have local connectivity
    • If DHCP address is obtained, perform the ping tests
      • Local gateway, remote IP address
  • Jitter
    • Most real-time media is sensitive to delay
    • If you miss a packet, there’s no retransmission
    • Jitter is the time between frames
  • Poor VoIP quality
    • High speed and low latency
    • Check the internet connection
    • Verify the local networking equipment
    • View the network performance
      • A packet capture would be useful
  • Latency
    • A delay between the request and the response
    • Some latency is expected and normal
    • Examine the response times at every step along the way
    • Packet capture can provide detailed analysis
  • Port flapping
    • Network interface goes up and down
      • Over and over again
    • Verify the cable
    • Move between switch interfaces
    • Replace bad hardware or cables