Tech
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TCP/IP Basics–The World of TCP/IP–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA Network+ (N10-007) NETWORK-PLUS Certification Prep Course Notes
TCP/IP BASICS Intro to IP Addressing & Binary Each computer on a TCP/IP network must have a unique IP address. IPv4 addresses are written as four octets, such as: 192.168.4.12 Each octet represents a binary string; 192, for example, is represented by 11000000 Dotted decimal notation–shorthand used to represent the 32 1’s & 0’s. 28 (256) combinations Each octet is valued between 0 and 255. Converting from binary to dotted decimal: Intro to ARP APR (Address Resolution Protocol) resolves IP addresses. ARP is what a computer uses when it knows the IP address, but needs the MAC address. Type ‘arp -a’ to see the ARP cache (shows a list of…
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Installing a Physical Network–The Physical Network–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA Network+ (N10-007) NETWORK-PLUS Certification Prep Course Notes
Installing a Physical Network Intro to Structured Cabling Structured cabling defines how we install cabling (i.e.–cable organization). Structured cabling systems will have: 1). Telecommunication closet/equipment room. This room will contain all switches & centralized stuff that runs out via, 2). Horizontal Runs to individual 3). workstations/work areas. TIA standards specify wiring standards for structured cabling. Patch panels terminate one end of horizontal runs. Patch cables connect switches to patch panels & computers to wall outlets. Terminating Structured Cabling RJ-45 crimps are used only on patch cables. Horizontal runs are terminated with 110-punchdowns. Note: Horizontal runs are punched down to the back of a patch panel on one end, and on…
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Ruby Programming Language Notes
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Modern Ethernet–The Physical Network–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA Network+ (N10-007) NETWORK-PLUS Certification Prep Course Notes
Modern Ethernet 100Base-T Full-duplex mode allows both sides of a conversation to occur at the same time. Half-duplex, you can “talk” or “listen” but not at the same time. 100BaseT (aka 100BaseTX) runs at 100 Mbps up to 100 meters. 100BaseFX, a fiber solution, runs at 100 Mbps up to 2 kilometers. Connecting Switches (Note: Connecting switches in a tree structure is common when networks are larger & more spread out, into clusters.) Straight-through cables have identical ends, such as 568B. Crossover cables have different ends–568A and 568B. Connect switches directly with crossover cables. Gigabit Ethernet & 10-Gigabit Ethernet Know your 1000Base types: names, distances, node numbers, etc. Know your…
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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”…
