Network Fundamentals: Top Picks
Firewall Topologies
In this section we are going to talk about the different ways a firewall can be set up. Depending on your needs, you can have a very simple firewal...
Media Access Control - MAC Addresses
A MAC address, or Media Access Control address, is a unique identifier assigned to a network interface controller (NIC) for use as a network addr...
Power over Ethernet - Understanding PoE Technol...
Power over Ethernet (PoE) was invented by PowerDsine back in 1997 and the first power injector (Midspan) was installed in 1998! Many manufacturespa...
DoS & DDoS Attacks
A Denial of Service (DoS) attack is a malicious attempt to disrupt the normal functioning of a website, server or network by flooding it with traff...
Featured Subcategories:
Netflow Articles:
NetFlow Analyzer: Free Download, Step-by-Step I...
In our previous article we explained how a Netflow Analyzer can help you gain visibility into your user traffic, application traffic and data flows...
Complete Guide to Netflow: How Netflow & its Co...
This article will cover the basics of Netflow, including its use cases, Netflow supported devices, Netflow history, and variants. We’ll also dive i...
Netflow: Monitor Bandwidth & Network Utilizatio...
Monitoring network traffic & bandwidth usage via Netflow is mandatory for any type and size network. Gaining visibility into user traffic, appl...
Netflow vs SNMP. Two Different Approaches to Ne...
SNMP (Simple Network Management Protocol) and Netflow are both popular protocols with admins, prized for their ability to give visibility over the ...
Network Protocols:
TCP Header Anaylsis - Section 2: TCP Sequence &...
This page will closely examine the Sequence and Acknowledgement numbers. The very purpose of their existence is related directly to the fact that t...
TCP Header Anaylsis - Section 7: TCP Data Paylo...
Finally, the last page of our incredible TCP Analysis. As most of you would expect, this section is dedicated to the DATA section that follows the ...
IP Protocol - Part 1: Binary & The Internet Pro...
To understand the Internet Protocol, we need to learn and understand Binary. It is very important to know and understand Binary because part of the...
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 popu...
IP Subnetting - Part 2: Subnet Masks & Their Ef...
There are a few different ways to approach subnetting and it can get confusing because of the complexity of some subnets and the flexibility they o...
The DNS Protocol - Part 1: Introduction
If you ever wondered where DNS came from, this is your chance to find out ! The quick summary on DNS's history will also help you understand why DN...
Transmission Control Protocol - Part 2: Quick O...
As previously mentioned on a number of occasions, TCP is one of the two protocols that lives at the Transport layer and is used to carry data from ...
TCP Header Anaylsis - Section 3: TCP Header Len...
The third field under close examination is the TCP Header length. There really isn't that much to say about the Header length other than to explain...
STP/ICMP Protocols:
Spanning Tree Protocol – Part 1: Understand STP...
One of the most used terms in network is LAN (Local Area Network). It’s a form of network that we encounter in our daily lives, at home, at work, s...
ICMP Protocol - Part 5: Source Quench Message A...
The ICMP - Source Quench message is one that can be generated by either a gateway or host. You won't see any such message pop up on your workstatio...
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 (...
ICMP Protocol - Part 4: Destination Unreachable...
The 'ICMP Destination unreachable' message is quite interesting, because it doesn't actually contain one message, but infact six! This means that t...
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VLANs - IEEE 802.1q Trunk Link Protocol Analysis
While the VLAN Tagging article briefly covered the IEEE 802.1q protocol this article will continue building upon it by further analyzing the IEEE 802.1q...
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 e...
VTP Pruning
VTP (VLAN Trunking Protocol) pruning is a feature that is used in Cisco switches to reduce unnecessary traffic in VLAN (Virtual Local Area Network) trun...
VLAN Security - Making the Most of VLANs
It's easy to see why virtual LANs have become extremely popular on networks of all sizes. In practical terms, multiple VLANs are pretty much the same as...
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 networ...
OSPF - Part 4: OSPF Neighbor States – OSPF Neighbor ...
This is the third article of our OSPF series which analyzes the different OSPF States routers go through during the OSPF discovery and neighbor forming ...
Routing Information Protocol - RIP
Routing Information Protocol (RIP) is a distance-vector routing protocol that is commonly used in small to medium-sized networks. It is one of the...
Enhanced Interior Gateway Routing Protocol - EIGRP
Enhanced Interior Gateway Routing Protocol (EIGRP), similar to IGRP, is a Cisco proprietary routing protocol that is used to exchange routing informatio...