Articles That Might Interest:

Cisco Firewalls

Understand & Configure NAT Reflection, NAT Loopba…

This article examines the concept of NAT Reflection, also known as NAT Loopback or Hairpinning, and shows how to configure a Cisco ASA Firewall running ASA version 8.2 and earlier plus ASA version 8…

Cisco Firewalls

Cisco ASA5500 (5505, 5510, 5520, etc) Series Fire…

The Cisco ASA 5500 series security appliances have been around for quite some time and are amongst the most popular hardware firewalls available in the market. Today Firewall.cx takes a look at how t…

Cisco Switches

Resolving Cisco Switch & Router ‘DHCP Server Pool…

In previous articles, we showed how it is possible to configure a Cisco router or Catalyst switch to provide DHCP server services to network clients. Everything usually works without a problem, howev…

VLAN Networks

The VLAN Concept - Introduction to VLANs

We hear about them everywhere, vendors around the world are constantly trying to push them into every type of network and as a result, the Local Area Network (LAN) we once knew starts to take a diffe…

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. Static NAT was mainly created to allow hosts o…

Cisco Switches

End-of-Sale and End-of-Life Announcement for the…

Cisco announces the end-of-sale and end-of-life dates for the Cisco Catalyst 3750G, 3560G, 3750-E, and 3560-E Series Switches. The last day to order the affected product(s) is January 30, 2013. Custo…

Cisco Routers

How To Configure Windows VPDN (PPTP) Dialup Conne…

Setting up a Windows VPDN connection is a required task in order to connect to a remote network. In previous articles we covered the set up of a VPDN - PPTP server on a Cisco router. Click here to fi…

Security Service Edge (SSE)

Security Service Edge (SSE) Limitations & Disadva…

This article explores the Security Service Edge (SSE) portion of Secure Access Service Edge (SASE) and the need for holistic cybersecurity protections. We lightly touch upon the drivers for tighter…

The OSI Model

The OSI Model: Layer 5 - Session Layer

The Session layer is responsible for setting up, managing and then tearing down sessions between Presentation layer entities. The Session layer also provides dialog control between devices, or nodes…

Network Address Translation - NAT

The Network Address Translation Table

After that simple and informative introduction to the NAT concept, it's time to find out more about how it works and this is where the NAT table comes in. The Network Address Translation (NAT) Table…

Linux - Unix

Updating Your Linux Server - How to Update Linux…

Like any other software, an operating system needs to be updated. Updates are required not only because of the new hardware coming into the market, but also for improving the overall performance and…

Ethernet Protocol, CSMA/CD, Collisions

Early Ethernet Collisions

In this example, we will refer to an imaginary Ethernet network consisting of Stations A and B and any number of other stations. The status of the network is such that the wire is idle (nobody is tal…