Although we live in an era of network virtualization and software defined networking, the traditional hardware ethernet switch is still at the backbone of most networks. Cisco switches have been among the leaders in this field. The original Catalyst series of switches (running on IOS software) are still in production and powering millions of networked […]
Icinga vs Zabbix vs Nagios – Comparison of IT/Network Monitoring Tools
Nagios, Zabbix and Icinga are three of the most popular software tools for network monitoring and management. These tools have a plethora of features and characteristics but their core purpose is to provide visibility into your network and IT systems by monitoring the health, performance, utilization etc of your critical infrastructure components. All three are […]
Fortinet Fortigate 30E vs 50E/51E vs 60E/61E/60F – Firewall Comparison
Fortinet has managed to become one of the top industry leaders in security infrastructure in a relatively short amount of time. In many cases they have managed to displace other traditional security vendors such as Cisco, Juniper, Checkpoint etc by offering more cost effective and flexible solutions. For example, in the company that I work […]
10 Best Network Engineer Certifications to Pursue for Your Career
Like all other areas in the field of Information Technology, networking is growing fast, and there’s a necessity for qualified professionals with the knowledge necessary to keep networks up and running, secure, and reliable. But even in the world of networking, there are a plethora of specializations an individual can take. One can choose to […]
Basic Cisco Switch Configuration
In my opinion, the Cisco switches are the best in the market. Versatile, reliable, flexible and powerful, the Cisco switch product line (such as the 2960, 3560, 3650, 3850, 4500, 6500, 9400 series etc) offer unparalleled performance and features. Although a Cisco switch is a much simpler network device compared with other devices (such as […]
11 Best Network Troubleshooting Software Tools (Free&Paid)
As a network engineer, you will be spending almost half of your time in troubleshooting issues arising in the network or solving problems related to IT and network conditions. Although there are several Windows or Linux commands that you can use on host computers to check for various connectivity issues, a professional should have a […]
DNS Port Number – What is Domain Name System – How DNS Works
DNS (Domain Name System) is the system that translates an Internet or Host name (that is easier for people to remember) to an IP address. In this article we’ll describe how DNS works, what port numbers are used for DNS protocol etc so keep reading for all info below. What is DNS A Domain Name […]
How to Configure Static Routing on Cisco IOS Routers (Examples)
Cisco IOS Routers support both static and dynamic routes. In small networks (2 to 5 routers) I would suggest to configure only static routes, especially if the network is not going to change much over time. Of course dynamic routing (using dynamic routing protocols such as RIP, OSPF, EIGRP) is much more flexible and scalable […]
Redistribution Between Cisco EIGRP into OSPF and Vice Versa (Example)
The most common scenario for big enterprise networks with multiple routers is to have a single IGP routing protocol (IGP = Interior Gateway Protocol) running between the routers in order to distribute all the routing information of the network. The most common IGP routing protocols used by today’s networks are OSPF, EIGRP (Cisco proprietary) and […]
Configuring Local Username and Password on a Cisco IOS Router
There are mainly two ways to authenticate to a Cisco router device (and also to other networking devices in general). Using an external authentication service (such as AAA server, Radius, TACACS etc) or by having local usernames and passwords on the device itself. In this article we will discuss how to setup a local username […]
How to Configure EIGRP on Cisco Routers (With Example)
Enhanced Interior Gateway Routing Protocol (EIGRP) is an enhanced version of the now obsolete IGRP. EIGRP is Cisco proprietary which means it is available only on Cisco routers and switches. EIGRP employs an algorithm referred to as the Diffusing Update Algorithm (DUAL) which guarantees fast convergence and loop-free operation at all times. It is an […]
Password Recovery for the Cisco ASA 5500 Firewall (5505,5510,5520 etc)
If you have lost the administrator password to access the security appliance you can recover the ASA password with the following steps: Recovering your Password on Cisco ASA Step1: Connect to the firewall using a console cable Step2: Power cycle the appliance (power off and then on) Step3: Press the Escape key to enter ROMMON […]
Cisco Spanning Tree Protocol Guide (STP Examples and Configuration)
Spanning Tree Protocol (STP) ensures a loop-free topology in a local area network (LAN) made up of switches. It is desirable to have redundant links in a switched LAN so that a single link failure cannot interrupt normal operation of the network. But redundant links may also introduce physical switching loops that are undesirable. STP […]