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Network Fundamentals: Top Picks

Network Fundamentals
Measuring network performance has always been a difficult and unclear task, mainly because most engineers and administrators are unsure which approac…
Network Fundamentals
A network is simply a group of two or more Personal Computers linked together. Many types of networks exist, but the most common types of networks ar…
Network Fundamentals
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 traffic…
Network Fundamentals
Network topologies can take a bit of time to understand when you're all new to this kind of cool stuff, but it's very important to fully understand t…

Featured Subcategories:

Netflow Articles:

Netflow
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…
Netflow
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
In this article, we explore the core principles of bandwidth management and examine how modern network monitoring technologies can assist in maintain…
Netflow
SNMP (Simple Network Management Protocol) and Netflow are both popular protocols with admins, prized for their ability to give visibility over the ne…

Network Protocols:

Domain Name System (DNS)
This section will deal with the analysis of the DNS packets by examining how DNS messages are formatted and the options and variables they contain. T…
Domain Name System (DNS)
The previous article covered the DNS Query message formats. In the article we analysed them in great detail and showed how various options are select…
IP Protocol
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 I…
TCP - UDP Protocol Analysis
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 TC…
TCP - UDP Protocol Analysis
This section contains one of the most well-known fields in the TCP header, the Source and Destination port numbers. These fields are used to specify…
TCP - UDP Protocol Analysis
This article shows the TCP Header and Segment. We explain where the TCP Header and Segment are located in an Ethernet frame and also briefly view the…
TCP - UDP Protocol Analysis
This page will closely examine the Sequence and Acknowledgement numbers. The very purpose of their existence is related directly to the fact that the…
Subnetting
When we subnet a network, we basically split it into smaller networks. For example, when a set of IP Addresses is given to a company, e.g 254 they mi…

STP/ICMP Protocols:

ICMP Protocol
The ICMP - Time Exceeded message is one which is usually created by gateways or routers. In order to fully understand this ICMP message, you must be…
Spanning Tree Protocol (STP)
Spanning Tree Protocol, Rapid STP port costs and port states are an essential part of the STP algorithm that affect how STP decides to forward or blo…
ICMP Protocol
As mentioned in the previous page, an Echo is simply what we networking engineers call a 'ping'. The Echo Reply is, as most would guess,  the 'p…
ICMP Protocol
The 'ICMP Destination unreachable' message is quite interesting, because it doesn't actually contain one message, but infact six! This means that the…

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VLAN Networks
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
Dynamic VLANs were introduced to grant the flexibility and complexity(!) that Static VLANs did not provide. Dynamic VLANs are quite rare because of their…
VLAN Networks
If you've read our previous article The VLAN Concept - Introduction to VLANs  then you should feel comfortable with terms such as 'VLAN', 'Stati…
VLAN Networks
The previous article introduced the VTP protocol, we examined how it can be used within a network, to help manage VLANs and ease the administrative overhe…

Routing
We are going to analyse what happens when routing occurs on a network (IP routing process). When I was new to the networking area, I thought that all you…
Routing
This article explains how OSPF uses Link State Advertisement (LSA) to exchange information about the network topology between routers. When a router recei…
Routing
Our previous article explained the purpose of Link State Update (LSU) packets and examined the Link State Advertisement (LSA) information contained within…
Routing
Open Shortest Path First (OSPF) is a popular routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working…

Network Address Translation - NAT
In our previous article, Network Address Translation (NAT) Overload - Part 1, we explained what NAT Overload is and how it works. This page deals with the…
Network Address Translation - NAT
Static NAT (also called inbound mapping) is the first mode we're going to talk about and also happens to be the most uncommon between smaller networks. S…
Network Address Translation - NAT
Before we dive into the deep waters of NAT, we need to make sure we understand exactly what NAT does. So let me give you the background of NAT, why it's h…
Network Address Translation - NAT
Dynamic NAT is the second NAT mode we're going to talk about. Dynamic NAT, like Static NAT, is not that common in smaller networks but you'll find it used…