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08/11/2025

If your mission was to secure an online bank portal, what is the first information you would demand in your briefing?

Let’s get your insight ??



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Clarence Warner
Darwolo Poronpaye
Computer Network engineering tutorial
Emmanuel Jutonue Woart
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08/06/2025

If an attacker compromises your workstation's boot process, how can they bypass your OS level defenses entirely?

07/19/2025

Network Address Translation for DUMMIES (NAT)!

What is NAT and why Do we use it (Real World Context)

In this post, we walk through how NAT works in real-world network environments with a fully configured lab you can try yourself!

Follow, Like, comment, and send us a message to get the full ZIP file of the lab setup. Perfect for hands-on learners and IT students.

Imagine This Situation (Real Enterprise Example)
You work for a company with 200 computers, printers, and servers inside the building. All devices use private IPs like 192.168.0.x/24. You only bought 1 public IP address from your ISP (203.0.113.1). You need all 200 employees to browse the internet.

Question:

How do 200 private IPs reach the public internet using only one public IP? Network Address Translation (NAT)

Network Address Translation (NAT) allows multiple users on the local network to access the internet using a single Public IP address by translating private IPs to the public IP to access the internet.

How does NAT manage multiple users on the same local network accessing the internet simultaneously?

NAT manages multiple users by giving each session or connection a unique port number and mapping it to the local device's private IPs and port number to route traffic to the correct device and application, and this process is called dynamic NAT because the port number changes on each request or session made by the users on the local network to access the Public internet.

Let's understand how NAT works simply:

Internal Private IP to external Public IP for outgoing traffic to the internet; External Public IP to internal Private IP for incoming traffic or replies, keeping local devices hidden by showing only the Public IP address to the public internet, and this process is called IP Masquerading that adds a layer of network security, keeping private IPs hidden from the Public internet.

Types of NAT

Static NAT – maps a specific private IP address to a public IP address, meaning it's a one-to-one mapping; only the assigned private IP that is mapped to the Public IP address will communicate; no other device can use that medium of communication. A web server hosted inside a LAN allows extended users to access the server through the mapped extended Public IP address.

Dynamic NAT - dynamic assign a public IP from a pool of available public addresses when a local device needs to communicate with the public internet. If all IPs in the dynamic NAT pool are in use, a new packet might be discarded or queued until an IP address is available, for clarity!
PAT - Port Address Translation allows multiple devices to share a single public IP address it's efficient in SOHO networks or local offices.

TekkNowCybersecurity | NetworkingDavid Bombal R3viveEmmanuel Jutonue WoartLinuxComputer Network engineering tutorial

07/18/2025

TekkNow Do you know your Brain is a slave to Repetition ? Whatever you do daily that’s your programming.

Watch junk ? You become junk.
Scroll aimlessly ? Your focus dies.
Talk negative ? You think small.

You don’t become what you want you become what you Repeat!

07/17/2025

DHCP for Dummies 👇

Dynamic Host Configuration Protocol (DHCP) is an automatic IP configuration system. It assigns IP addresses to other nodes, like IP addresses, subnet masks, gateways, and DNS on the network. DHCP listens on UDP port 68 from the client to the server and responds to the client on port 67. You may ask, what is a port? a network port is like a door on a device that allows network traffic to enter or leave.

Why do we need DHCP?

Without DHCP we may need to manually assign IP addresses to each device; this might lead to IP conflicts or wasted time, with DHCP devices automatically get IP addresses when they connect. It simplifies large network imagine configuring 500 devices by hand.

What does DHCP provide?

DHCP provides a unique identifier for devices on the network, an IP address, a subnet mask that defines the network boundary, a router IP for internet or other network access, and DNS to resolve domain names to IP addresses like google.com.

DHCP Process, how it works think about DHCP as a four-step process between the client and the DHCP server. It's referred to as DORA for deeper understanding.

Discover Offer Request Acknowledge (DORA).

How DHCP works in the real world: step 1 Discover the client sending a broadcast message is there any DHCP server out there? Step 2: Offer the dhcp respond with an IP to the client. Step 3 Request the client say yes to the request I want the IP you offer, step 4 Acknowledge the server respond this IP is now yours.

07/15/2025

With Cisco – We just got recognized as one of their top fans! 🎉

07/15/2025

DNS For Dummies 👇

DNS helps translate human-friendly name like https://www.coursera.org/ into IP addresses like 3.213.11.145. To practicalize this, open your command prompt in Windows and type nslookup -type=A coursera.com. The –type=A request is the IPv4 A record. You may ask what the A record is. (An A record is a type of DNS record that maps a domain name to its IPv4 address.) It’s like your phonebook; you don't dial numbers, you dial names.

How does DNS work in the real world?

When we type coursera.com in the browser, a DNS query starts. You may ask what a DNS query is like asking the internet for a phone number, in other word.
Ex: Query is like, Check in my contact book and give me the number of Mom.

Let's break this down in simple steps:

DNS = Phonebook of the Internet

Query = The question your device asks is, what is the IP of this domain?

Answer = The IP address of the website.

Let's look at the type of DNS server in the real world and how it works!
Local DNS Server the local DNS server is the first place our computers or devices reach out to when they need to turn a domain name into an IP address. Imagine you are asking somebody for directions. The local DNS server is like asking your closest neighbor first because they might already know the answer.

Where is the local DNS server in real life?

It's usually built into your router or your computer or provided by the local ISP (Internet Service Provider). It's local because it's the DNS server closest to you physically and logically.

What does it do?

You type google.com in your browser, and your device sends the request to the local DNS resolver, maybe your router or ISP's server. The resolver checks its cache to see if it's saved the answer; if it has, it will return the IP instantly. If not, it goes into the DNS hierarchy to find the answer. Hierarchy is a layer structure of how domain names are organized and looked up from the top root down to the specific website requested.

Breakdown of DNS hierarchy from root server to authoritative server!

Imagine you're browsing the internet and you type into your web browser, Where is example.com?

Root DNS Servers: These are the very top level of the DNS hierarchy; they are like the gatekeepers they don't know the exact IP, but they know who to ask next. When you enter learning.com in your browser, they say, Try the .com server.; they are the ones in charge of domains ending in .com, which is the TLD DNS Servers Top Level Domain. They handle requests like .com, .org, etc. Once the root servers point your browser to .com servers, the TLD servers will say, For learning.com, ask the Authoritative DNS Servers; they have the official information you need. It’s like being directed from one location to your final destination. Authoritative DNS Server: They are the official record keepers that store the actual DNS records for the domain name. There are only 13 sets of root servers in the world, and they guide everything.

TekkNowCybersecurity | NetworkingCiscoEmmanuel Jutonue WoartClarence WarnerNetworkChuck

07/14/2025

LinuxUniversity of the PeopleCybersecurity | NetworkingClarence Warner

Get Ubuntu Server one of three ways; by using Multipass on your desktop, using MAAS to provision machines in your data centre or installing it directly on a server.

07/14/2025

Let's begin the Linux Mastery Journey and become job-ready Linux System Administrators. We will focus on practical skills that are used in the real world.

What is Linux, Really?

When people say Linux, they often mean the whole operating system (OS), but in reality, Linux is the kernel, not the entire OS.

The Kernel is:

The core of the operating system

Sits between the hardware and user-level programs

Manages CPU, memory, devices, and system calls

Think of the kernel like an engine in the car; it's not the whole car, but it powers everything else.

What is the Linux Distribution (Distro)

Linux is a complete operating system built on the Linux kernel, bundled with user space, tools, a shell, a package manager, and an editor.

Drivers, services, default apps

Configuration tailored for specific use and cases, read and explore. Linux Distribution https://www.geeksforgeeks.org/linux-unix/8-most-popular-linux-distributions/

Linux Filesystem

The Root of Everything: /

Linux doesn't use drive letters like Windows (C:); instead, it starts with a single root directory, written as a backslash (/). Everything else branches out of this root, like files, folders, devices, ectara.
Imagine backslash / as a trunk of a tree, and all other folders are branches growing from it.

Why It’s Structured this way to keep system files separate from user files, making it easy for us to back up, secure, and manage the system. Follows a standard called FHS (Filesystem Hierarchy Standard) so it's consistent across all Linux systems.

Setting Up a Virtual Lab

A safe space to break things without consequence and implement real-world practical Linux administration to prepare us for the real world.

Install VirtualBox; it is free software that allows you to run virtual machines (VMs) on your host machine. Download from https://virtualbox.org

Ubuntu Server is a lightweight, command-line version of Ubuntu—perfect for learning core Linux. Download from https://ubuntu.com/download/server

Stay tuned for a video walkthrough for lab setup.

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Let's look at key folders we will see under the root directory /.

07/13/2025

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