Articles
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Articles:
The OSI Model: Layer 5 - Session Layer
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The OSI Model: Layer 4 - Transport Layer
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The OSI Model: Layer 3 - Network Layer
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The OSI Model: Layer 2 - Datalink Layer
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The OSI Model: Layer 1 - Physical Layer
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Suggested Articles:
Ethernet Protocol, CSMA/CD, Collisions
The IEEE 802.3 Frame Format
The following is a description of the Ethernet Frame Format described in the IEEE 802.3 Specification. The 802.3 Specification defines a 14 byte Data…
TCP - UDP Protocol Analysis
TCP Header Anaylsis - Section 4: TCP Flag Options
As we have seen in the previous pages, some TCP segments carry data while others are simple acknowledgements for previously received data. The popula…
Network Cabling
Serial Direct Cable Connection, DB9, DB25, COM Po…
This article covers the popular serial ports on workstations, servers and laptop computers. We cover serial data transfer, port pinouts, port speeds…
ICMP Protocol
ICMP Protocol - Part 6: Redirect Messages
The ICMP - Redirect Message is always sent from a gateway to the host and the example below will illustrate when this is used.
Putting it simply (be…
Featured Subcategories:
Netflow Articles:
Netflow: Monitor Bandwidth & Network Utilization…
Monitoring network traffic & bandwidth usage via Netflow is mandatory for any type and size network. Gaining visibility into user traffic, applic…
Complete Guide to Netflow: How Netflow & its Comp…
This article will cover the basics of Netflow, including its use cases, Netflow supported devices, Netflow history, and variants. We’ll also dive int…
Netflow vs SNMP. Two Different Approaches to Netw…
SNMP (Simple Network Management Protocol) and Netflow are both popular protocols with admins, prized for their ability to give visibility over the ne…
NetFlow Analyzer: Free Download, Step-by-Step Ins…
In our previous article we explained how a Netflow Analyzer can help you gain visibility into your user traffic, application traffic and data flows w…
Wi-Fi Key Generator
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Cisco Password Crack
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VLAN Networks
VLAN InterSwitch Link (ISL) Protocol Analysis
Deciding whether to use ISL or IEEE 802.1q to power your trunk links can be quite confusing if you cannot identify the advantages and disadvantages of eac…
VLAN Networks
VLAN Tagging - Understanding VLANs Ethernet Frames
We mentioned that Trunk Links are designed to pass frames (packets) from all VLANs, allowing us to connect multiple switches together and independently co…
VLAN Networks
The VLAN Concept - Introduction to VLANs
We hear about them everywhere, vendors around the world are constantly trying to push them into every type of network and as a result, the Local Area Netw…
VLAN Networks
VTP Introduction & Modes
The invention of VLANs was very much welcomed by all engineers and administrators, allowing them to extend, redesign and segment their existing network wi…
Routing
Introduction to Routing Protocols
Distance Vector, Link State RIP, IGRP, EIGRP, OSPF
Routing protocols were created for routers. These protocols have been designed to allow the exchange…
Routing
Link State Routing Protocols
Link State routing protocols do not view networks in terms of adjacent routers and hop counts, but they build a comprehensive view of the overall network…
Routing
OSPF - Part 2: How OSPF Protocol Works & Basic Concept…
This article covers basic OSPF concepts and operation. We explain how OSPF works, how OSPF tables are built on an OSPF-enabled router and their purpose (N…
Routing
OSPF - Part 6: OSPF LSA Types - Purpose and Function o…
Our previous article explained the purpose of Link State Update (LSU) packets and examined the Link State Advertisement (LSA) information contained within…
Virtualization & VM Backup
Ultimate Guide: Install Windows 11 on VMware ESXi – Ea…
In this article, we’ll show you how to setup or install Microsoft Windows 11 on VMware’s ESXi servers and bypass the Trusted Platform Module version 2.0 (…
Cisco Routers
Cisco Router Basics
This article will focus on Cisco's routers which can be found in almost any organization due to their popularity and market penetration. Cisco has a numb…
Cisco Switches
Complete Guide to DHCP Snooping, How it Works, Concept…
This article covers popular Layer 2 & Layer 3 network attacks with a focus on DHCP Starvation Attacks, Man-in-the-Middle attacks, unintentional rogue…
Cisco Routers
Configuring Cisco SSL VPN AnyConnect (WebVPN) on Cisco…
Our Web SSL VPN article written back in 2011 introduced this new wave of VPN services. This article extends the topic by covering the installation a…







