Companies these days need to deal with and manage vast inventories of network and IT assets. Keeping track of these assets, tagging them, and knowing their status at all times is essential to the operations of any modern company. Image Source As you’d expect, this is a big job but network inventory software makes it […]
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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.
Table Of Contents
What is DNS A Domain […]
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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 […]
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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 […]
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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 […]
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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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