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Articles:
The DNS Protocol - Part 1: Introduction
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Suggested Articles:
The OSI Model
The OSI Model: Layer 1 - Physical Layer
The Physical layer has two responsibilities: it sends bits and receives bits. Bits come only in values of 1 or 0. The Physical layer communicates dir…
TCP - UDP Protocol Analysis
TCP Header Anaylsis - Section 2: TCP Sequence & A…
This page will closely examine the Sequence and Acknowledgement numbers. The very purpose of their existence is related directly to the fact that the…
Network Protocols
ISDN Layers, Protocols & Components
Our previous article was an Introduction To The ISDN Protocol. This article dives a bit deeper by examining ISDN Layers, Protocols & Components…
Network Cabling
CAT5, CAT5e, CAT6 UTP X-Over / Cross-over Cable
The cross-over (or crossover) CAT5 UTP cable has to be one of the most used cables after the classic straight-thru cable. The cross-over cable allows…
Featured Subcategories:
Netflow Articles:
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: 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…
Wi-Fi Key Generator
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Cisco Password Crack
Decrypt Cisco Type-7 Passwords on the fly!
VLAN Networks
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 h…
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 co…
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
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 their…
Routing
OSPF - Part 5: Analysis of OSPF Link State Update (LSU…
This article explains how OSPF uses Link State Advertisement (LSA) to exchange information about the network topology between routers. When a router recei…
Routing
Interior Gateway Protocol - IGRP
IGRP (Interior Gateway Routing Protocol) is a Cisco proprietary distance-vector routing protocol used in enterprise networks to exchange routing informati…
Routing
Enhanced Interior Gateway Routing Protocol - EIGRP
Enhanced Interior Gateway Routing Protocol (EIGRP), similar to IGRP, is a Cisco proprietary routing protocol that is used to exchange routing information…
Routing
OSPF - Part 4: OSPF Neighbor States – OSPF Neighbor Fo…
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…
Virtualization & VM Backup
SysAdmin Day 2020 - Get your Free Amazon Voucher & Gif…
SysAdmin Day has arrived, and with it, gratitude for all the unsung heroes that 2020 has needed. Your hard work has made it possible for all of us to keep…
Cisco Wireless
Wireless (Wifi) WEP WPA WPA2 Key Generator
The Firewall.cx Wireless LAN Key Generator will allow the generation of a WEP or WPA ASCII based encryption key and will provide the equivalent HEX or…
Cisco Switches
Cisco Nexus 7000 Series Module Shutdown and Removal Pr…
This article explains the procedure that should be followed to correctly shutdown/powerdown a Cisco Nexus 7000 series module and remove it from the chassi…
Cisco Routers
Configuring Point-to-Point GRE VPN Tunnels - Unprotect…
Generic Routing Encapsulation (GRE) is a tunneling protocol developed by Cisco that allows the encapsulation of a wide variety of network layer protocols…







