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Network Fundamentals: Top Picks

Network Fundamentals
In today's world, securing your home network is more important than ever. With the increasing number of cyberattacks, data breaches, and online fraud…
Network Fundamentals
Network Switches are the evolution of Hubs and Repeaters, and enable the creation of networks by connecting multiple devices together. They are criti…
Network Fundamentals
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 firewall…
Network Fundamentals
The first step in controlling broadcast and multicast traffic is to identify which devices are involved in a broadcast or multicast storm. The follow…

Featured Subcategories:

Netflow Articles:

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
SNMP (Simple Network Management Protocol) and Netflow are both popular protocols with admins, prized for their ability to give visibility over the ne…
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
Monitoring network traffic & bandwidth usage via Netflow is mandatory for any type and size network. Gaining visibility into user traffic, applic…

Network Protocols:

TCP - UDP Protocol Analysis
Our fifth section contains some very interesting fields that are used by the TCP transport protocol. We see how TCP helps control how much data is tr…
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…
TCP - UDP Protocol Analysis
As we have seen in the previous pages, some TCP segments carry data while others are simple acknowledgements for previously received data. The popula…
IP Protocol
This article explains the 'Network-ID' and 'Host-ID' concept found in IP addressing and subnetting. We analyse the structure of IP addresses and netw…
TCP - UDP Protocol Analysis
Understanding how each protocol fits into the OSI Model is essential for any network engineer. This page analyses how TCP is classified as a 'transpo…
TCP - UDP Protocol Analysis
This article is an introduction to the 7-page TCP Header analysis section that follows. We briefly view each section of the TCP Header and then move…
TCP - UDP Protocol Analysis
This article covers the UDP protocol. We examine the structure of the UDP header, the protocols that use UDP as a transport plus a lot more. Some co…
Subnetting
Routing and Communication between subnets is the main topic here. This article analyses communications between subnets. We provide examples on differ…

STP/ICMP Protocols:

Spanning Tree Protocol (STP)
In this article we will examine the Spanning Tree Bridge ID structure, explain why it has increments of 4096, how VLAN information is embedded (for P…
ICMP Protocol
The Internet Control Message Protocol (ICMP), is a very popular protocol and actually part of an Internet Protocol (IP) implementation. Because IP wa…
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…
ICMP Protocol
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 workstation…

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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
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
VTP (VLAN Trunking Protocol) pruning is a feature that is used in Cisco switches to reduce unnecessary traffic in VLAN (Virtual Local Area Network) trunks…
VLAN Networks
VLANs are usually created by the network administrator, assigning each port of every switch to a VLAN. Depending on the network infrastructure and securit…

Routing
This is the thrid article of our 6-part OSPF series (see below) that describes how OSPF routers perform neighbor relationship and adjacency. We’ll examine…
Routing
Hybrid routing protocols are a combination of distance-vector and link-state routing protocols, and are used to provide a more efficient and scalabl…
Routing
Open Shortest Path First (OSPF) is a popular routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working…
Routing
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 pr…

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
NAT Overload is the most common NAT method used throughout all networks that connect to the Internet. This is because of the way it functions and the limi…
Network Address Translation - NAT
After that simple and informative introduction to the NAT concept, it's time to find out more about how it works and this is where the NAT table comes in…