Network Fundamentals: Top Picks
Network Fundamentals
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 firewall…
Network Fundamentals
Controlling Broadcasts and Multicasts
The first step in controlling broadcast and multicast traffic is to identify which devices are involved in a broadcast or multicast storm. The follow…
Network Fundamentals
Introduction to Content Switching - Application &…
Content switches (also sometimes called application switches) is a class of network device that is becoming increasingly common in medium to large si…
Network Fundamentals
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 traffic…
Featured Subcategories:
Netflow Articles:
Netflow
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
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…
Netflow
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…
Netflow
ML-Based Security Analytics in NetFlow Analyzer…
This article explores how machine learning (ML) and network flow telemetry can be used to establish behavioral baselines, detect anomalous asset acti…
Network Protocols:
TCP - UDP Protocol Analysis
TCP Header Anaylsis - Section 5: TCP Window Size…
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…
Domain Name System (DNS)
The DNS Protocol - Part 3: DNS Query Message Form…
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…
TCP - UDP Protocol Analysis
TCP Header Anaylsis - Section 7: TCP Data Payload…
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
Transmission Control Protocol - Part 3: The TCP H…
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…
IP Protocol
IP Protocol - Part 3: IP Classes, Network & Host…
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
Transmission Control Protocol - Part 1: Introduct…
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…
Supernetting & CIDR
What is Supernetting (Route Summarization) & How…
Supernetting is the opposite of of subnetting, and is also known as route aggregation or CIDR (Classless Inter-Domain Routing). Supernetting is a tec…
Domain Name System (DNS)
The DNS Protocol - Part 2: DNS Queries & Resoluti…
This section will help you understand how the DNS queries work on the Internet and your home network. There are two ways to use the domain name syste…
STP/ICMP Protocols:
ICMP Protocol
ICMP Protocol - Part 4: Destination Unreachable M…
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
ICMP Protocol - Part 5: Source Quench Message Ana…
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…
Spanning Tree Protocol (STP)
Spanning Tree Protocol – Part 1: Understand STP P…
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, stu…
Spanning Tree Protocol (STP)
Spanning Tree Protocol – Part 3: Bridge ID, Prior…
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…
Wi-Fi Key Generator
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VLAN Networks
Static VLANs
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
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
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…
VLAN Networks
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) trunks…
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
Distance Vector Routing Protocols
Distance Vector routing protocols use frequent broadcasts (255.255.255.255 or FF:FF:FF:FF) of their entire routing table every 30 sec. on all their interf…
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
Routed Protocols
We all understand that TCP/IP, IPX-SPX are protocols which are used in a Local Area Network (LAN) so computers can communicate between with each other and…
Network Address Translation - NAT
Dynamic NAT - Part 2
Our previous article, Dynamic NAT - Part 1, covered the basic idea of Dynamic Network Address Translation. We are now going to take a closer look at the p…
Network Address Translation - NAT
Dynamic NAT - Part 1
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…
Network Address Translation - NAT
Network Address Translation (NAT) Overload - Part 1
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
Network Address Translation (NAT) Concepts
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…




