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!"

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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nfographic comparing similarities and differences between OSPFv2 and OSPFv3 routing protocols, including link-state features, metrics, areas, packet types, router ID, advertised routes, multicast addresses, authentication, and LSA types.
CCNA September 1, 2019

OSPFv2 vs OSPFv3: Key Differences and Similarities

OSPFv3 is a routing protocol for IPv6, just as OSPFv2 is for IPv4. While both share core principles, there are vital differences in their operation. OSPFv3 serves as the IPv6 equivalent to OSPFv2 for exchanging prefixes, making it essential for modern networks handling dual-stack environments. In IPv6, the network address is referred to as the...
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Network topology diagram showing Router1, Router2, Router3, and Router4 in Area 0, with labels for OSPF verification commands like show ip ospf neighbor and debugging.
CCNA September 1, 2019

OSPF Troubleshooting and Verification Guide

OSPF (Open Shortest Path First) is a cornerstone of enterprise routing, widely tested in CCNA and CCNP exams. Its complexity stems from link-state operations, making troubleshooting and verification crucial for network stability and certification success. This guide explores real-world scenarios, like multi-area OSPF in large networks, to equip students with practical skills. Therefore, troubleshooting OSPF...
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Diagram illustrating Cisco interface bandwidth configuration with routers, default bandwidths, and real-world applications.
CCNA September 1, 2019

Understanding Cisco Interface Bandwidth: Configuration, Verification, and Routing Impacts

In Cisco networking, the interface bandwidth value plays a crucial role in routing decisions without affecting the actual link speed. For CCNA students, this is key to understanding basic router configurations and why routing protocols might choose suboptimal paths. CCNP learners will appreciate its ties to advanced topics like OSPF cost calculations and QoS policies....
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Network topology diagram showing OSPF passive interface on Router1's LAN connection with IP addresses and router IDs.
CCNA September 1, 2019

OSPF Passive Interfaces: Configuration and Best Practices (Updated 2025)

In OSPF (Open Shortest Path First), OSPF passive interface is a configuration that prevents the router from sending or receiving OSPF Hello packets on a specific interface while still allowing the connected network to be advertised in OSPF updates. This is crucial for CCNA and CCNP students to understand as it optimizes bandwidth, enhances security,...
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