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 […]
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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 […]
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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 […]
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This post is by no means an exhaustive tutorial about Cisco Routers and how to configure their numerous features. It is a step-by-step guide for the most basic configuration commands needed to make the router operational. When you first power up a new Cisco Router, you have the option of using the “setup” utility which […]
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This is a post for people new to networking that have just started learning IP addressing and the basis of routing and subnetting. Every host or device on a TCP/IP network MUST have an IP address assigned in order to communicate with other devices. An IP address consists of a network part and a host […]
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When it comes to authentication services in networking and IT systems in general, the best practice is to have a centralized authentication system which contains the user account credentials in a secure way and controls all authentication and authorization. This is why Active Directory in Microsoft environments is such a useful and powerful authentication scheme. […]
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I have read tens of books (both in ebook format and also hard copy textbooks) in my networking professional career over the last 18 years. In fact, all of my preparation for my Cisco and other IT certifications was based on book studying (in addition to hands-on practice of course). Personally, I believe that having […]
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WiFi is an incredibly useful communication protocol that is widely used. In fact, it’s the de facto standard used to create wireless networks in homes, businesses, public spaces etc. However, it’s not uncommon for signal strength to degrade due to a variety of factors, including distance from the access point, obstacles, competing WiFi signals, and […]
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For businesses, the task of network and IT infrastructure monitoring remains highly important. A company cannot afford to ignore the security and performance of its network and IT resources. Nagios remains one of the most popular solutions for IT infrastructure monitoring today. An entire suite of software allows businesses to take control and have visibility […]
[Continue reading]CISCO ASA 5505 CISCO ASA 5510 The two smallest ASA Firewall models, the 5505 and the 5510, are the only ones that have two types of licenses. They can be ordered either with a Base License or a Security Plus License. Many customers of mine are always asking me what the difference is between the […]
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Although I have been a TCP/IP networking professional for decades, in the last 10 years I’m also involved in network security as well. One of the tasks I’m responsible to do in my work environment is to either coordinate or perform network assessment projects on my own. A major part of a network security assessment […]
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It is fair to say that there are few things more important to your daily security than the security of your Internet connection and hence your privacy and sensitive data. Everyone has heard horror stories of their information being stolen via covert means online, and nobody wants to be subject to the nightmares that can […]
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In this article we will consider the topic of Cisco IOS Zone Based Firewall (ZBFW). Cisco IOS Zone Based Firewall allows us to define Security Zones and to give each zone its own policy. What is Zone Based Firewall At the very beginning of Cisco routers, the implementation of firewall functionality on IOS router devices […]
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