Author: Asad Ijaz

NetworkUstad's lead networking architect with CCIE certification. Specializes in CCNA exam preparation and enterprise network design. Authored 2,800+ technical guides on Cisco systems, BGP routing, and network security protocols since 2018. Picture this: I'm not just someone who writes about tech; I'm a certified expert in the field. I proudly hold the titles of Cisco Certified Network Professional (CCNP) and Cisco Certified Network Associate (CCNA). So, when I talk about networking, I'm not just whistling in the dark; I know my stuff! My website is like a treasure trove of knowledge. You'll find a plethora of articles and tutorials covering a wide range of topics related to networking and cybersecurity. It's not just a website; it's a learning hub for anyone who's eager to dive into the world of bits, bytes, and secure connections. And here's a fun fact: I'm not a lone wolf in this journey. I'm a proud member and Editor of Team NetworkUstad. Together, we're on a mission to empower people with the knowledge they need to navigate the digital landscape safely and effectively. So, if you're ready to embark on a tech-savvy adventure, stick around with me, Asad Ijaz Khattak. We're going to unravel the mysteries of technology, one article at a time!"
A graphic titled "Evolution of Malware and Network Defenses" featuring four icons and labels. From left to right: a floppy disk icon labeled "1986 Brain Virus," a worm icon labeled "2003 Network Worms," a brain icon labeled "2024 AI Malware," and a padlock icon labeled "Network Defense." The background is dark with circuit-like patterns.
Cyber Security September 13, 2019

What is Malware and Malicious Software? (Updated 2025)

Updated: October 19, 2025—Includes latest threats and network defenses. Malware, or malicious software, is a program or file designed to disturb computer processes and operations or gain unauthorized entry to the computer system, often via network protocols like RDP or SMB, without the user’s knowledge or permission. Malware has become a common term for all […]
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Infographic on thwarting cybercriminals in 2025 with icons for early warning systems, vulnerability databases, sharing cyber intelligence, ISM standards, and new laws and regulations.
Cyber Security September 12, 2019

Thwarting Cybercriminals: Master Key Measures and Strategies for Cybersecurity Enthusiasts in 2025

As a cybersecurity and networking expert with extensive experience in securing enterprise environments, I’ve seen firsthand how cybercriminals evolve their tactics. Thwarting cybercriminals isn’t easy, but companies, governments, and organizations are taking proactive steps to limit and discourage these threats. In this article, we’ll explore key actions and measures, updated for 2025, with practical insights […]
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Infographic of network security showing a hacker targeting WAN/LAN router, users on laptops, and defenses like shield, badge, and firewall bricks
Cyber Security September 12, 2019

Cyber Security Threats and Defenses: A Comprehensive Guide for 2025

Cyber security threats are a growing concern worldwide, escalating with AI and ransomware in 2025. Individuals and organizations rely on networks, making intrusions devastating. Computer networks are necessary for everyday activities, and both individuals and organizations depend on their computers and networks. Intrusion to these computers by an illegal person can result in a network […]
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Infographic showing Cisco router VTY access control using Telnet/SSH and ACLs. Includes a centered title, configuration steps, and a network diagram with PC0 denied and PC1 permitted access to router R3.
CCNA September 11, 2019

How to Configure Standard ACLs to Secure VTY Ports

All Cisco routers and switches do not allow remote access by default via terminal programs like PuTTY or Tera Term. Remote connectivity options include Telnet (VTY Port) or SSH. SSH provides encrypted sessions and is strongly recommended by Cisco for remote administration due to Telnet’s vulnerabilities. Prerequisites for CCNA/CCNP Students However, if your router’s Cisco […]
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Infographic illustrating ACL statistics with a table showing permit and deny statements, matches, and explanations, featuring a laptop and router with permit and deny arrows
CCNA September 10, 2019

ACL Statistics in Cisco Networks: Monitoring Matches with show access-lists

Access Control Lists (ACLs) are essential for filtering traffic in Cisco networks. For CCNA students, understanding statistics helps verify if rules are working as intended. CCNP candidates should note how stats aid in troubleshooting complex setups like multi-interface ACLs. After an ACL has been configured and applied to an interface, it can block or permit […]
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Infographic showing three steps to edit standard ACLs: sequence numbers, router config commands, and named ACL examples in Cisco networking.
CCNA September 10, 2019

How to Edit Standard ACLs

Network administrators sometimes want to edit standard ACLs. As you know, each new entry you add to the Access Control List (ACL) appears at the bottom of the list, and the router assigns a sequence number to that entry automatically. Standard ACL statements are added to running-config files, but there is no built-in way to […]
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Diagram illustrating standard ACL configuration with a router blocking traffic from host 192.168.2.2 to network 192.168.4.0/24.
CCNA September 9, 2019

How to Configure standard ACLs

Standard ACLs permit or deny traffic based on source addresses. They differentiate routes on a network using the IP address. The port and destination of the packet are not evaluated. Standard ACLs only contain a list of addresses or address ranges and a statement as to whether access to or from that address is permitted […]
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Diagram of TCP three-way handshake process showing SYN, SYN-ACK, and ACK exchanges between two hosts for connection establishment.
CCNA September 2, 2019

Understanding TCP Three-Way Handshake: A Comprehensive Guide (Updated 2025)

In networking, the TCP three-way handshake (often called a “TCP conversation”) establishes reliable connections, which is crucial for Access Control Lists (ACLs) to filter traffic effectively. ACLs manage inbound and outbound traffic based on IP addresses, ports, and TCP flags. This article explains TCP fundamentals before diving into ACL integration, helping CCNA students grasp transport […]
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Diagram and configuration commands for setting up OSPFv3 on a network.
CCNA September 1, 2019

How to Configure OSPFv3: Complete Guide (Updated 2025)

Figure 1 shows the reference topology for configuring OSPFv3. You can also see the commands for configuring OSPFv3 for IPv6 unicast and link-local addresses on the interfaces of Router1. As identified in the referenced topology, assume that Router2, Router3, and Router4 interfaces have already been configured with the global IPv6 and link-local addresses. This topology […]
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Illustration of interconnected routers demonstrating link-local IPv6 address concept
CCNA September 1, 2019

What is a Link-Local IPv6 Address – Exclusive Introduction

Routers configured with dynamic routing protocols such as OSPF or EIGRP must send and receive routing protocol messages with their directly connected neighbors. The routers exchange messages between neighbors on the same subnet. These messages are always sent from the router’s source IPv4 address. Link-local IPv6 addresses are perfect for this purpose. The address also […]
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