Network Fundamentals: Top Picks
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 Broadcast
The term "Broadcast" is used very frequently in the networking world . You will see it in most networking books and articles, or see it happening o...
Power over Ethernet - Understanding PoE Technol...
Power over Ethernet (PoE) was invented by PowerDsine back in 1997 and the first power injector (Midspan) was installed in 1998! Many manufacturespa...
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 foll...
Featured Subcategories:
Netflow Articles:
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 ...
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...
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: 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...
Network Protocols:
Transmission Control Protocol - Part 3: The TCP...
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 t...
The DNS Protocol - Part 4: DNS Response Message...
The previous article covered the DNS Query message formats. In the article we analysed them in great detail and showed how various options are sele...
The Supernetting / CIDR Chart
This articles build upon our previous pages covering what is Supernetting (Route Summarization) & How Supernets Work and Supernetting In-...
What is Supernetting (Route Summarization) & Ho...
Supernetting is the opposite of of subnetting, and is also known as route aggregation or CIDR (Classless Inter-Domain Routing). Supernetting is a t...
TCP Header Anaylsis - Section 5: TCP Window Siz...
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 ...
TCP Header Anaylsis - Section 2: TCP Sequence &...
This page will closely examine the Sequence and Acknowledgement numbers. The very purpose of their existence is related directly to the fact that t...
The DNS Protocol - Part 1: Introduction
If you ever wondered where DNS came from, this is your chance to find out ! The quick summary on DNS's history will also help you understand why DN...
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:
ICMP Protocol - Part 4: Destination Unreachable...
The 'ICMP Destination unreachable' message is quite interesting, because it doesn't actually contain one message, but infact six! This means that t...
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...
ICMP Protocol - Part 6: Redirect Messages
The ICMP - Redirect Message is always sent from a gateway to the host and the example below will illustrate when this is used.
Putting it simply (...
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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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...
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 secur...
Comparing Traditional Flat & VLAN Networks
Designing and building a network is not a simple job. VLANs are no exception to this rule, in fact they require a more sophisticated approach because of...
VLAN Security - Making the Most of VLANs
It's easy to see why virtual LANs have become extremely popular on networks of all sizes. In practical terms, multiple VLANs are pretty much the same as...
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 a...
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 inte...
OSPF - Part 4: OSPF Neighbor States – OSPF Neighbor ...
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 ...
The IP Routing Process - Step-by-Step Analysis
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 yo...