Terms and Such 1101 A+ Flashcards
(74 cards)
1
Q
802.11
A
– Local area network (LAN)
– High speed, Internet access
2
Q
Near-field communication (NFC)
A
- Short-distance networking
– 4 centimeters or less
– Data transfers or authentication - Common on mobile phones and smart watches
– Payment method on your wrist - Use it for authentication without typing a password
– Hospital workstations, warehouses, manufacturing
3
Q
Fluorescent vs. LED backlighting
A
- LED-backlit LCD display
– Backlight is LEDs instead of florescent
– LEDs around the edge of the screen
– An array of LEDs behind the screen
– The latest laptops are LED-backlit - CCFL - Cold Cathode
– Fluorescent Lamp
– Higher voltage and power needed
– Added thickness to the display
– No longer a common backlight
– Older laptops will use these
4
Q
Backlight and inverter
A
- LCD displays need a backlight
– Florescent lamp/LED to LCD display to your eyes - Some laptops have inverters - Turn DC into AC
- Verify backlight
– Look closely and use a flashlight - May need to replace the LCD inverter or display
– Choose carefully
5
Q
Digitizer
A
- Use a pen-like device as input
– Stylus input - Useful for graphical input
-– Digitizer responds to touch - No keyboard required - Used commonly on laptop / tablets
– Or hybrid devices
6
Q
Microsoft 365
A
- Outlook, Exchange
– Microsoft’s email service
– Usually the same for Hotmail and Outlook.com - Select the items to synchronize
– Changes in Outlook will appear on the mobile device - Data types
– Mail
– Pictures, music, video
– Calendar
– Contacts
7
Q
TCP – Transmission Control Protocol
A
- 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
8
Q
UDP – User Datagram Protocol
A
- Connectionless - No formal open/close to the connection
- “Unreliable” delivery
– No error recovery
– No reordering of data or retransmissions - No flow control
– Sender determines the amount of data transmitted
9
Q
FTP - File Transfer Protocol
A
- tcp/20 (active mode data), tcp/21 (control)
– Transfers files between systems - Authenticates with a username and password
– Some systems use a generic/anonymous login - Full-featured functionality - List, add, delete, etc
10
Q
SSH - Secure Shell
A
- Encrypted communication link - tcp/22
- Looks and acts the same as Telnet
11
Q
Telnet
A
- Telnet – Telecommunication Network - tcp/23
- Login to devices remotely
– Console access - In-the-clear communication
– Not the best choice for production systems
12
Q
SMTP - Simple Mail Transfer Protocol
A
- SMTP - Simple Mail Transfer Protocol
– Server to server email transfer - tcp/25 - Also used to send mail from a device to a mail server
– Commonly configured on mobile devices and email clients - Other protocols are used for clients to receive email
– IMAP, POP3
13
Q
DNS - Domain Name System
A
- Converts names to IP addresses - udp/53
– www.professormesser.com = 162.159.246.164 - These are very critical resources
– Usually multiple DNS servers are in production
14
Q
DHCP - Dynamic Host Configuration Protocol
A
- Automated configuration of IP address, subnet mask and
other options - udp/67, udp/68
– Requires a DHCP server
– Server, appliance, integrated into a SOHO router, etc. - Dynamic / pooled
– IP addresses are assigned in real-time from a pool
– Each system is given a lease and must renew at set intervals - DHCP reservation
– Addresses are assigned by MAC address in the DHCP server
– Manage addresses from one location
15
Q
POP3 / IMAP
A
- Receive emails from an email server
– Authenticate and transfer - POP3 - Post office Protocol version 3
– tcp/110
– Basic mail transfer functionality - IMAP4 - Internet Message Access Protocol v4
– tcp/143
– Includes email inbox management from multiple clients
16
Q
SMB - Server Message Block
A
- Protocol used by Microsoft Windows
– File sharing, printer sharing
– Also called CIFS (Common Internet File System) - Using NetBIOS over TCP/IP
(Network Basic Input/Output System)
– udp/137 - NetBIOS name services (nbname)
– tcp/139 - NetBIOS session service (nbsession) - Direct over tcp/445 (NetBIOS-less)
– Direct SMB communication over TCP without the NetBIOS transport
17
Q
SNMP - Simple Network Management Protocol
A
- Gather statistics from network devices
– Queries: udp/161
– Traps: udp/162
18
Q
LDAP (Lightweight Directory Access Protocol
A
- LDAP (Lightweight Directory Access Protocol) - tcp/389
- Store and retrieve information in a network directory
– Commonly used in Microsoft Active Directory
19
Q
RDP - Remote Desktop Protocol
A
- Share a desktop from a remote location over tcp/3389
- Remote Desktop Services on many Windows versions
- Can connect to an entire desktop or just an application
- Clients for Windows, macOS, Linux, Unix, iPhone, Android, and others
20
Q
Switches
A
- Bridging done in hardware
– Application-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
– Includes routing functionality
21
Q
Patch Panels
A
- Combination of punch-down blocks and RJ-45 connectors
- Runs from desks are made once
– Permanently punched down to patch panel - Patch panel to switch can be easily changed
– No special tools
– Use existing cables
22
Q
Firewalls
A
- Filters traffic by port number
– OSI layer 4 (TCP/UDP)
– Some firewalls can filter based on the application - Can encrypt traffic into/out of the network
– Protect your traffic between sites - Can proxy traffic
– A common security technique - Most firewalls can be layer 3 devices (routers)
– Usually sits on the ingress/egress of the network
23
Q
Hub
A
- “Multi-port repeater”
– Traffic going in one port is repeated to every other port - Everything is half-duplex
- Becomes less efficient as network traffic increases
- 10 megabit / 100 megabit
24
Q
Cable modem
A
- Broadband
– Transmission across multiple frequencies
– Different traffic types - Data on the “cable” network
– DOCSIS (Data Over Cable Service Interface Specification) - High-speed networking
– Speeds up to 1 Gigabit/s are available - Multiple services
– Data, voice, video
25
DSL modem
* ADSL (Asymmetric Digital Subscriber Line)
– Uses telephone lines
* Download speed is faster than the upload
speed (asymmetric)
– ~10,000 foot limitation from the central office (CO)
– 52 Mbit/s downstream / 16 Mbit/s upstream are
common
– Faster speeds may be possible if closer to the CO
26
ONT
* Optical network terminal
– Fiber to the premises
* Connect the ISP fiber network to the copper network
– Demarcation point (demarc) in the data center
– Terminal box on the side of the building
* Line of responsibility
– One side of the box is the ISP
– Other side of the box is your network
27
Network Interface Card (NIC)
* The fundamental network device
– Every device on the network has a NIC
– Computers, servers, printers, routers, switches, phones, tablets, cameras, etc.
* Specific to the network type
– Ethernet, WAN, wireless, etc.
* Often built-in to the motherboard
– Or added as an expansion card
* Many options - Single port, multi-port, copper, fiber
28
802.11a
* Operates in the 5 GHz range
– Or other frequencies with special licensing
* 54 megabits per second (Mbit/s)
* Smaller range than 802.11b
– Higher frequency is absorbed by objects in the way
29
802.11b
* Operates in the 2.4 GHz range
* 11 megabits per second (Mbit/s)
* Better range than 802.11a, less absorption problems
* More frequency conflict
– Baby monitors, cordless phones, microwave ovens, Bluetooth
30
802.11g
* Operates in the 2.4 GHz range
* 54 megabits per second (Mbit/s) - Similar to 802.11a
* Backwards-compatible with 802.11b
* Same 2.4 GHz frequency conflict problems as 802.11b
31
802.11n (Wi-Fi 4)
* Operates at 5 GHz and/or 2.4 GHz
– 40 MHz channel widths
* 600 megabits per second (Mbit/s)
– 40 MHz mode and 4 antennas
* 802.11n uses MIMO
– Multiple-input multiple-output
– Multiple transmit and receive antennas
32
802.11ac (Wi-Fi 5)
* Operates in the 5 GHz band
– Less crowded, more frequencies (up to 160 MHz channel bandwidth)
* Increased channel bonding - Larger bandwidth usage
* Denser signaling modulation
– Faster data transfers
* Eight MU-MIMO downlink streams
– Twice as many streams as 802.11n
– Nearly 7 gigabits per second
33
802.11ax (Wi-Fi 6)
* Operates at 5 GHz and/or 2.4 GHz
– 20, 40, 80, and 160 MHz channel widths
* 1,201 megabits per second per channel
– A relatively small increase in throughput
– Eight bi-directional MU-MIMO streams
* Orthogonal frequency-division multiple access (OFDMA)
– Works similar to cellular communication
– Improves high-density installations
34
RFID (Radio-frequency identification)
* It’s everywhere
– Access badges
– Inventory/Assembly line tracking
– Pet/Animal identification
– Anything that needs to be tracked
* Radar technology
– Radio energy transmitted to the tag
– RF powers the tag, ID is transmitted back
– Bidirectional communication
– Some tag formats can be active/powered
35
DNS server
* Domain Name System
– Convert names to IP addresses
– And vice versa
* Distributed naming system
– The load is balanced across many different servers
* Usually managed by the ISP or IT department
– A critical resource
36
DHCP server
* Dynamic Host Configuration Protocol
– Automatic IP address configuration
* Very common service
– Available on most home routers
* Enterprise DHCP will be redundant
– Usually running on central servers
37
File server
* Centralized storage of documents,spreadsheets, videos, pictures, and any other files
– A fileshare
* Standard system of file management
– SMB (Server Message Block), Apple Filing Protocol (AFP), etc.
* The front-end hides the protocol
– Copy, delete, rename, etc.
38
Print server
* Connect a printer to the network
– Provide printing services for all network devices
* May be software in a computer
– Computer is connected to the printer
* May be built-in to the printer
– Network adapter and software
* Uses standard printing protocols
– SMB (Server Message Block), IPP (Internet Printing Protocol), LPD (Line Printer Daemon)
39
Mail server
* Store your incoming mail
– Send your outgoing mail
* Usually managed by the ISP or the IT department
– A complex set of requirements
* Usually one of the most important services
– 24 x 7 support
40
Syslog
* Standard for message logging
– Diverse systems, consolidated log
* Usually a central logging receiver
– Integrated into the SIEM
* You’re going to need a lot of disk space
41
Spam
* Unsolicited messages
– Email, forums, etc.
* Various content
– Commercial advertising
– Non-commercial proselytizing
– Phishing attempts
42
Load balancers
* Distribute the load
– Multiple servers
– Invisible to the end-user
* Large-scale implementations
– Web server farms, database farms
* Fault tolerance
– Server outages have no effect - Very fast convergence
43
Proxy server
* An intermediate server
– Client makes the request to the proxy
– The proxy performs the actual request
– The proxy provides results back to the client
* Useful features
– Access control, caching, URL filtering, content scanning
44
SCADA / ICS
* Supervisory Control and Data Acquisition System
– Large-scale, multi-site Industrial Control Systems (ICS)
* PC manages equipment
– Power generation, refining,
manufacturing equipment
– Facilities, industrial, energy, logistics
* Distributed control systems
– Real-time information
– System control
– Requires extensive segmentation
– No access from the outside
45
IoT (Internet of Things) devices
* Appliances
– Refrigerators
* Smart devices
– Smart speakers respond to voice commands
* Air control
– Thermostats, temperature control
* Access
– Smart doorbells
* May require a segmented network
– Limit any security breaches
46
The DHCP Process (DORA)
* Step 1: Discover - Client to DHCP Server
– Find all of the available DHCP Servers
* Step 2: Offer - DHCP Server to client
– Send some IP address options to the client
* Step 3: Request - Client to DHCP Server
– Client chooses an offer and makes a formal request
* Step 4: Acknowledgment - DHCP Server to client
– DHCP server sends an acknowledgment to the client
47
Automatic Private IP Addressing (APIPA)
* A link-local address - No forwarding by routers
* IETF has reserved 169.254.0.0 through 169.254.255.255
– First and last 256 addresses are reserved
– Functional block of169.254.1.0 through 169.254.254.255
* Automatically assigned
– Uses ARP to confirm the address isn’t currently in use
48
LANs
* Local Area Networks
* A group of devices in the same broadcast domain
49
Virtual LANs
* Virtual Local Area Networks
* A group of devices in the same broadcast domain
* Separated logically instead of physically
50
Configuring VLANs
* Virtual Local Area Networks
– A group of devices in
the same broadcast domain
51
VPNs
* Virtual Private Networks
– Encrypted (private) data traversing a public network
* Concentrator
– Encryption/decryption access device
– Often integrated into a firewall
* Many deployment options
– Specialized cryptographic hardware
– Software-based options available
* Used with client software
– Sometimes built into the OS
52
Satellite networking
* Communication to a satellite
– Non-terrestrial communication
* High cost relative to terrestrial networking
– 50 Mbit/s down, 3 Mbit/s up are common
– Remote sites, difficult-to-network sites
* High latency
– 250 ms up, 250 ms down
– Starlink advertises 40 ms and is working on 20 ms
* High frequencies - 2 GHz
– Line of sight, rain fade
53
Cable broadband
* Broadband
– Transmission across multiple frequencies
– Different traffic types
* Data on the “cable” network
– DOCSIS (Data Over Cable Service Interface
Specification)
* High-speed networking
– 50 Mbits/s through 1,000+ Mbit/s are common
* Multiple services
– Data, voice, video
54
DSL
* ADSL (Asymmetric Digital Subscriber Line)
– Uses telephone lines
* Download speed is faster than the upload speed
(asymmetric)
– 200 Mbit/s downstream / 20 Mbit/s upstream
are common
– ~10,000 foot limitation from the central office (CO)
– Faster speeds may be possible if closer to the CO
55
USB (Universal Serial Bus)
* Simplify connections - Printers, storage devices, keyboard, mouse
* USB 1.1
– Low speed: 1.5 megabits per second, 3 meters
– Full speed: 12 megabits per second, 5 meters
* USB 2.0 - 480 megabits per second, 5 meters
* USB 3.0 - SuperSpeed
– 5 gigabits per second, ~3 meters
– Standard does not specify a cable length
56
VGA (Video Graphics Array)
* DB-15 connector
– More accurately called DE-15
* Blue color
– PC System Design Guide
* Analog signal
– No digital
– Image degrades after 5 to 10 meters
57
DVI (Digital Visual Interface)
* Single and dual link
– Single link; 3.7 Gbps (HDTV at 60 fps)
– Dual link; 7.4 Gbps (HDTV at 85 fps)
– No audio support
* DVI-A
– Analog signals
* DVI-D
– Digital signals
* DVI-I
– Integrated
– Digital and analog in the same connector
58
SATA (Serial AT Attachment)
* SATA Revision 1.0 - SATA 1.5 Gbit/s, 1 meter
* SATA Revision 2.0 - SATA 3.0 Gbit/s, 1 meter
* SATA Revision 3.0 - SATA 6.0 Gbit/s, 1 meter
* SATA Revision 3.2 - SATA 16 Gbit/s, 1 meter
* eSATA (external SATA)
– Matches the SATA version - 2 meters
59
F-connector
* Cable television
– Cable modem
– DOCSIS
(Data Over Cable Service Interface Specification)
* RG-6 cable - Threaded connector
60
Hard disk drives (HDD)
* Non-volatile magnetic storage - rapidly rotating platters
* Random-access
– Retrieve data from any part of the drive at any time
* Moving parts
– Spinning platters, moving actuator arm
– Mechanical components limit the access speed
– Mechanical components can also break
61
Solid-state drives (SSD)
* Non-volatile memory - No moving parts
* Very fast performance - No spinning drive delays
62
Optical drives
* Small bumps read with a laser beam
– Microscopic binary storage
* Relatively slow
– Archival media
* Many different formats - CD-ROM, DVD-ROM, Blu-ray
* Internal and external drives
– For those uncommon application installations
63
RAID
* Redundant Array of Independent Disks
– They’re also inexpensive disks.
* Different RAID levels - Some redundant, some not
* RAID 0 – Striping
* RAID 1 - Mirroring
* RAID 5 – Striping with Parity
* Nested RAID - RAID 1+0 (a.k.a. RAID 10) - A stripe of mirrors
64
RAID 0 - Striping
* File blocks are split between
two or more physical drives
– High performance
– Data written quickly
* No redundancy
– A drive failure breaks the array
– Raid 0 is zero redundancy
65
RAID 1 - Mirroring
* File blocks are duplicated between two or more physical drives
* High disk utilization
– Every file is duplicated
– Required disk space is doubled
* High redundancy
– Drive failure does not affect data availability
66
Dual-voltage input options
* Voltage varies by country
– US/Canada – 120 volts of AC (VAC), 60 hertz (Hz)
– Europe – 230 VAC, 50 Hz
* Manually switch between 120 V and 230 V
– Get your meter!
– Or use an auto-switching power supply
* Don’t plug a 120 V power supply into
a 230 V power source!
67
Duplex Printing
– Save paper
– Print on both sides of the page without manually flipping over the paper
– Not all printers can do this
68
Cloud computing characteristics
* Rapid elasticity
– Scale up and scale down as needed
– Seamless to everyone
– The cloud enables instant resource provisioning
* High availability
– Systems are always available
– Redundancy provides availability
* File synchronization
– Information can be duplicated across cloud locations
69
Virtualization
* One computer, many operating systems
– macOS, Windows 11, Linux Ubuntu, all at the same time!
* Separate OS, independent CPU, memory, network, etc.
– But really one computer
* Host-based virtualization
– Your normal desktop plus others
* Standalone server that hosts virtual machines
– Enterprise-level
70
Cross-platform virtualization
* Windows / macOS / Linux doesn’t do everything
– Each OS has strengths and weaknesses
* Run different operating systems at the same time
– Move between each OS seamlessly
– No rebooting
* Save time and resources
– One physical computer
71
6 steps to troubleshooting?
1. Establish a theory
2. Test the theory
3. Create a plan of action
4. Implement the solution
5. Verify full system functionality
6. Document findings
72
Troubleshooting hardware problems: POST and boot
* Blank screen on boot
– Listen for beeps
– Bad video, bad RAM, bad CPU
– BIOS configuration issue
* BIOS time and setting
– Maintained with the motherboard battery
– Replace the battery
* Attempts to boot to incorrect device
– Set boot order in BIOS configuration
– Confirm that the startup device has
a valid operating system
– Check for media in a startup device
73
Troubleshooting hardware problems: Bluescreens and spontaneous shutdowns
* Startup and shutdown BSOD
– Bad hardware, bad drivers, bad application
* Use Last Known Good, System Restore, or Rollback Driver
– Try Safe Mode
* Reseat or remove the hardware - If possible
* Run hardware diagnostics
– Provided by the manufacturer
– BIOS may have hardware diagnostics
74
Troubleshooting hardware problems: 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
