LAN Basics Data Encapsulation: PDUs Ethernet Frame Structure [ Preamble (7) | SFD (1) | Destination MAC (6) | Source MAC (6) | Type/Length (2) | Data | FCS (4) ] Ethernet Header (14 bytes) Preamble + SFD (not technically part of header) Ethernet Trailer (4 bytes) MAC Address (6 bytes) Hexadecimal and Decimal Quick…
CLI vs GUI Connecting via Console Port CLI Modes Configuration Files Two types: To save configuration: write write memory copy running-config startup-config Password Encryption Use enable secret instead of enable password (more secure) service password-encryption no service password-encryption enable secret 5 xxx # Type 5: MD5 encryption enable password 7 xxx # Type 7: Cisco…
Model and protocol OSI model Open Systems Interconnection model (open standard), created by ISO, consists of 7 layers Adjacent and Same Layer Interaction L7 (Application Layer) L6 (Presentation Layer) L5 (Session Layer) Data flow in OSI model L4 (Transport Layer) L3 (Network Layer) L2 (Data Link Layer) L1 (Physical Layer) Acronyms for memorizing OSI Please…
After spending time with cloud platforms like Azure, AWS, and DigitalOcean — as well as Type 2 hypervisors (like VirtualBox) — I decided to try something new: a Type 1 hypervisor installed directly on hardware. My choice? The open-source, free, and powerful Proxmox VE (Virtual Environment). Here’s a step-by-step walkthrough of how I installed and…
Recently, I got a used Cisco 881 router that was already configured (asking for a login and password when it started). The previous owner didn’t remember the credentials, so I had to reset it to factory settings. It turned out to be more difficult than I thought — here’s what I learned. 👇 1️⃣ ROM…
Connections and Speed Ethernet Standards (Copper) IEEE 802.3i, 802.3u, 802.3ab, 802.3an – standards with different data transmission speeds and names Speed Name (common) IEEE (standard) Name (informal) 10 Mbps Ethernet 802.3i 10BASE-T 100 Mbps Fast Ethernet 802.3u 100BASE-T 1 Gbps Gigabit Ethernet 802.3ab 1000BASE-T 10 Gbps 10 Gig Ethernet 802.3an 10GBASE-T UTP (Unshielded Twisted Pair)…
A computer network is a digital telecommunications network that allows nodes to share resources. Nodes: Client vs Server Switch Router Firewall A firewall (or a next-generation firewall) monitors and controls network traffic based on configured rules. It can be placed inside (after the router) or outside the network (before the router). There are two types…