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Suggested Articles:

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…
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…
The OSI Model
The Transport layer is responsible for providing mechanisms for multiplexing upper-layer application, session establishment, data transfer and tear d…
Ethernet Protocol, CSMA/CD, Collisions
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…

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Netflow Articles:

Monitoring network traffic & bandwidth usage via Netflow is mandatory for any type and size network. Gaining visibility into user traffic, applic…
This article will cover the basics of Netflow, including its use cases, Netflow supported devices, Netflow history, and variants. We’ll also dive int…
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…
In this article, we explore the core principles of bandwidth management and examine how modern network monitoring technologies can assist in maintain…

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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
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 T…
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…
VLAN Networks
We mentioned that Trunk Links are designed to pass frames (packets) from all VLANs, allowing us to connect multiple switches together and independently co…

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 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
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…
Routing
Enhanced Interior Gateway Routing Protocol (EIGRP), similar to IGRP, is a Cisco proprietary routing protocol that is used to exchange routing information…

Cisco Routers
The DNS protocol is used to resolve FQDN (Fully Qualified Domain Names) to IP addresses around the world. This allows us to successfully find and connect…
Network Protocol Analyzers
This article will help you understand TCP SYN Flood Attacks, show how to perform a SYN Flood Attack (DoS attack) using Kali Linux & hping3 and correct…
Windows Servers
FREE Hyper-V & VMware Backup:  FREE for Firewall.cx readers for a Limited Time!  Download Now! Virtualization is an abstraction layer that…
Cisco Wireless
Cisco Wireless Controllers (WLC) support the configuration of Link Aggregation (IEEE 802.3ad - LAG) which bundles the controller ports into a single port…