Network Fundamentals: Top Picks
Network Fundamentals
Securing Your Home Network
In today's world, securing your home network is more important than ever. With the increasing number of cyberattacks, data breaches, and online fra...
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 traff...
Network Fundamentals
Next-Gen Firewalls & Topologies. Designing & Bu...
Next-generation firewalls (NGFWs) and DMZ zones are two critical components of network security that work hand in hand to protect an organization's...
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 ...
Featured Subcategories:
Netflow Articles:
Netflow
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...
Netflow
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
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 ...
Netflow
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...
Network Protocols:
TCP - UDP Protocol Analysis
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 ...
Subnetting
IP Subnet Calculator
This free online Subnet Calculator provides a fast and easy way to calculate all aspects of any IP Address and Subnet Mask. Simply enter your des...
Supernetting & CIDR
The Supernetting / CIDR Chart
This articles build upon our previous pages covering what is Supernetting (Route Summarization) & How Supernets Work and Supernetting In-...
TCP - UDP Protocol Analysis
Transmission Control Protocol - Part 4: In-Dept...
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 mov...
Subnetting
IP Subnetting - Part 1: The Basic Concepts
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 ...
Subnetting
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...
TCP - UDP Protocol Analysis
Transmission Control Protocol - Part 1: Introdu...
Understanding how each protocol fits into the OSI Model is essential for any network engineer. This page analyses how TCP is classified as a 'trans...
Domain Name System (DNS)
The DNS Protocol - Part 3: DNS Query Message Fo...
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....
STP/ICMP Protocols:
Spanning Tree Protocol (STP)
Spanning Tree Protocol – Part 3: Bridge ID, Pri...
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...
ICMP Protocol
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...
Spanning Tree Protocol (STP)
Spanning Tree Protocol – Part 2: Rapid STP Port...
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 b...
Spanning Tree Protocol (STP)
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...
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VLAN Networks
VLAN Tagging - Understanding VLANs Ethernet Frames
We mentioned that Trunk Links are designed to pass frames (packets) from all VLANs, allowing us to connect multiple switches together and independently ...
VLAN Networks
Dynamic VLANs
Dynamic VLANs were introduced to grant the flexibility and complexity(!) that Static VLANs did not provide. Dynamic VLANs are quite rare because of thei...
VLAN Networks
VLANs - Access & Trunk Links
If you've read our previous article The VLAN Concept - Introduction to VLANs then you should feel comfortable with terms such as 'VLAN', 'Sta...
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) trun...
Routing
OSPF - Part 3: OSPF Adjacency & Neighbor Forming Pro...
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 exami...
Routing
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...
Routing
OSPF - Part 1: Introduction, OSPF Packet Structure, ...
Open Shortest Path First (OSPF) is a popular routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) worki...
Routing
OSPF - Part 5: Analysis of OSPF Link State Update (L...
This article explains how OSPF uses Link State Advertisement (LSA) to exchange information about the network topology between routers. When a router rec...
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...
Network Address Translation - NAT
Static NAT - Part 2
The previous page (Static NAT - Part 1) helped us understand what exactly happens with Static NAT and how it works, and we saw a few examples of how to ...
Network Address Translation - NAT
Static NAT - Part 1
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.
...
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 li...