Networking & Infrastructure
Core networking concepts: TCP/IP, edge computing, 5G, and the infrastructure that moves data around.
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Ethernet Basics–The Physical Network–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA Network+ (N10-007) NETWORK-PLUS Certification Prep Course Notes
The Physical Network Ethernet Basics What is Ethernet? The Ethernet frame (of data) never really changes! Max frame is 1,500 bytes. Ethernet is defined by the IEEE 802.3 standard. The IEEE has defined many versions of Ethernet. For the test, be able to recognize the Ethernet naming syntax. 802.3 standards: 802.3a 802.3b 802.3i 802.3ae and more Standard Nomenclature (for Ethernet): 10 Base 5 ’10’ is the speed in Mbps ‘5’ is the length of the cable (5 for 500m, But today the only value we’ll see here is ‘T’.) ‘Base’–only one channel on the entire bandwidth. or, ‘Broad’–Broadband is ethernet that runs like cable TV (with lots of channels or…
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Cabling & Topology–The Physical Network–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA Network+ (N10-007) NETWORK-PLUS Certification Prep Course Notes
The Physical Network Cabling & Topology Network Topologies ‘Star-Bus’ topology is considered a hybrid topology. When each host is interconnected this is considered a fully meshed topology. Logical topology is the electronic circuit flow of frames. Topology is the organization of how the 1’s & 0’s (binary data) in the form of frames, move from host to host. Star-Bus topology is the primary topology that we use today. Ethernet uses exclusively ‘Star-Bus’. If you’re plugging a computer into a network, it’s probably using Ethernet, & it’s probably using ‘Star-Bus’. MESH is a topology that’s pretty much unique to wireless networks. Everybody connects to everybody else. Fully meshed vs partially meshed…
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Understanding Networks–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA Network+ (N10-007) NETWORK-PLUS Certification Prep Course Notes
Understanding Networks Network Models What is a model? Models are used to represent how networks function. There are 2 very popular network models: the OSI 7-Layer model, & the TCP/IP model OSI Model vs. TCP/IP Model OSI Model (older; more detailed) 7- Application 6- Presentation 5- Session 4- Transport 3- Network 2- Data Link 1- Physical TCP/IP Model (more modern; not as detailed/complicated/more simplified) 4- Application 3- Transport 2- Internet 1- Network Interface (Link) Notes: The OSI model is being supplanted with the TCP/IP model. The TCP Internet layer most closely matches the OSI Network layer. Meet The Frame (Packets) Devices on a network send & receive data in discreet…
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Security & Organization–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes
Securing Computers Threats The term “security” encompasses host- and network-based security, and physical security. Common threats include man-in-the-middle attacks, DoS, and DDoS attacks. Symptoms of such attacks (Flags!) include renamed system files, missing files, & more. DoS–Denial of Service; DDoS–Distributed Denial of Service. Zero Day–a new threat that no one has seen before. Dealing With Threats Host-based security includes patching, anti-malware, and a firewall. Network-based security includes IDS, IPS, & firewalls. UTM (Unified Threat Management) includes IDS/IPS, firewalls, and anti-malware; available in the cloud. IDS–Intrusion Detection Systmes IPS–Intrusion Prevention Systems; these systems are more active! Endpoint Management Physical Security Physical security includes perimeter security, room locks, and individual device security.…
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Portable Computing Security & More–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes
Portable Computing Security & More The Internet Telnet & SSH The Telnet and the Secure Shell (SSH) protocols provide command line access to remote systems. Telnet runs on TCP port 23; SSH runs on TCP port 22. Telnet is unencrypted; SSH is encrypted. Telnet uses Port 23. Telnet: One of the earliest application protocols; allows access to another computer; A remote command line tool; a powerful tool; allows you to get to the command line on another comuter. To access a Telnet server, you need a Telnet client (similar to how in order to access a web server you need a web client, aka–web browser). Putty is a popular Telnet…
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The Essentials of Networking–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes
The Essentials of Networking Network Card Troubleshooting Use Device Manager –> NIC properties for information/configuration. Change duplex and wake-on LAN settings there Link lights show connectivity, activity, and (sometimes) speed. Full-Duplex–the NIC is talking & listening at the same time. Half-Duplex– Wake-on LAN–wakes up a computer from sleeping if certain information comes in (a so-called ‘magic packet’). Working With Connections–NETSTAT The ‘netstat’ command shows important information about connections. Use netstat switches ‘-n’ and ‘-a’ as needed. Consider a 3rd-party tool, such as TCPView as an alternative to netstat. TCPView is from SysInternals website. Netstat–shows statistics for different connections (usually TCP/UDP) ex: Windows folder sharing–(Port 445) TCPView is a ‘3rd-party’ tool…
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Troubleshooting Operating Systems–NETWORKING ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes
Troubleshooting Operating Systems Windows Recovery Environment WinRE (Windows recovery environment) WinRE provides access to essential troubleshooting tools WinPE (Windows pre-installation environment) Advanced options offer System Restore, System Images, & more Command Prompt option opens the Windows Command Shell. Advanced Startup Options To get to ‘Safe mode’ options in Windows 8/10, select option in ‘System Configuration’ for Safe boot. Alternatively, intentionally crash your system several times in a row to get Advanced options. ‘Startup Settings’ offer debugging, boot logging, Safe Mode, & more. Troubleshooting Boot Problems A black screen on a booted computer often indicates a video driver problem. Get to Safe Mode & try “Roll Back Driver” or “Update Driver”…
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Working With the Command-Line Interface–NETWORKING ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes
Working With the Command-Line Interface Understanding the CLI All operating systems offer a command line interface (CLI). A specific CLI is called a ‘shell’; most OSes provide multipole shell choices. All shells have a prompt to type in commands. Many commands use switches ( -n, -a, etc.) All shells offer some form of help. (Type <help> or /?) Navigating the CLI: Windows/Linux Use the ‘cd’ command in all OSes to move the prompt to different folders/directories. Make sure you can use the ‘cd’ command in Windows, Mac and Linux environments to navigate a system. (Mac & Linux are based on Unix.) To change drives in Windows, type the drive letter…
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Maintaining Operating Systems–NETWORKING ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes
Maintaining Operating Systems Patch Management Windows 7 Update gives the user the ability to choose which updates to install and when. Windows 10 Update locks down the update system more, the only option is to pause the update and choose active hours. Patch management in Ubuntu Linux offers more options for updating. Updating with macOS is pretty much automated, like Windows 10. Working With Discs Error checking runs ‘chkdsk’ on a disk partition to check for bad sectors. Trimming allows data to be written in individual pages termed “available for use” Optimizing trims blocks in disks to allow for new data to be written in partially full blocks. Working With…
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Windows OS Under the Hood–NETWORKING ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes
Windows OS Under the Hood! What is the Registry? The Registry is the primary database for every Windows system. Registry hold settings. Registry is critical, without it, Windows won’t run!!! We use the ‘regedit’ (Registry Editor) utility to manually edit the Registry. The Registry has five root keys into which all data is organized. HKLM (Hkey local machine)–defines all the settings for a particular computer. Processes Every program currently running on a system is a process. Processes all use process IDs (PID) We use utilities like Task Manager to kill errant processes. At any moment our computer can be running hundreds of programs. These programs can be broken down into…



