Articles
To read the articles in this section, simply click on the article title or read button on the far right (if visible).
Use the below filters to customise the number of articles displayed or search for specific title topics/keywords.
| Articles | |
|---|---|
| Read | |
| Read | |
| Read | |
|
Articles:
The OSI Model: Layer 5 - Session Layer
| Read |
|
Articles:
The OSI Model: Layer 4 - Transport Layer
| Read |
|
Articles:
The OSI Model: Layer 3 - Network Layer
| Read |
|
Articles:
The OSI Model: Layer 2 - Datalink Layer
| Read |
|
Articles:
The OSI Model: Layer 1 - Physical Layer
| Read |
Suggested Articles:
TCP Header Anaylsis - Section 1: TCP Source & Des…
This section contains one of the most well-known fields in the TCP header, the Source and Destination port numbers. These fields are used to specify…
The OSI Model: Layer 4 - Transport Layer
The Transport layer is responsible for providing mechanisms for multiplexing upper-layer application, session establishment, data transfer and tear d…
The Novell Proprietary Frame Format
Novell's Proprietary Frame Format was developed based on a preliminary release of the 802.3 specification. After Novell released its proprietary form…
The DNS Protocol - Part 4: DNS Response Message F…
The previous article covered the DNS Query message formats. In the article we analysed them in great detail and showed how various options are select…
Featured Subcategories:
Netflow Articles:
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 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…
Complete Guide to Netflow: How Netflow & its Comp…
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 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…
All-in-one protection for Microsoft 365
FREE Hyper-V & VMware Backup
Enterprise-Class Cloud & Network Monitoring
Wi-Fi Key Generator
Network and Server Monitoring
Follow Firewall.cx
Recommended Downloads
Cisco Password Crack
Decrypt Cisco Type-7 Passwords on the fly!
Bandwidth Monitor
Free PatchManager
Security Podcast
Firewall Analyzer
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…
VTP Protocol - In-Depth Analysis
The previous article introduced the VTP protocol, we examined how it can be used within a network, to help manage VLANs and ease the administrative overhe…
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', 'Stati…
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 co…
OSPF - Part 3: OSPF Adjacency & Neighbor Forming Proce…
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…
OSPF - Part 1: Introduction, OSPF Packet Structure, OS…
Open Shortest Path First (OSPF) is a popular routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working…
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 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 o…
How To Configure Router On A Stick - 802.1q Trunk To C…
Router-on-a-stick is a term frequently used to describe a setup up that consists of a router and switch connected using one Ethernet link configured as an…
How and Why You Should Verify IOS Images On Cisco Rout…
Chances are we’ve all needed to upgrade our Cisco’s device IOS software at some point. While upgrading the IOS software on a Cisco device is considered to…
Cisco 4507R+E Layer 3 Installation: Redundant WS-X45-S…
It's no news that we here at Firewall.cx enjoy writing about our installations of Cisco equipment and especially devices that we don’t get to see and play…
DHCP Option 82 Message Format, Analysis. DHCP Snooping…
This article provides in-depth analysis of DHCP Option 82 (DHCP Relay Agent) which is one of the +180 DHCP Options available to the DHCP protocol and used…