Enterprise Network on GNS3 - Part 5 - Data Center

The article is the fifth of the series of the articles discussing the enterprise network configuration. The article focus on the Data Center (DC) configuration. DC consists of the two devices – Server1 and the switch vIOS-Ser-I. Of course, the DC network with a single switch and the server is far away from any known […]
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Enterprise Network on GNS3 - Part 4 - Cisco ASAv-I

This is the fourth from the series of the articles that discuss configuration of the enterprise network. The article explains configuration of the device ASAv-I. The device is a Cisco Adaptive Security Virtual Appliance (ASAv) version 9.6(1) installed on qcow2 Qemu disk. The ASAv-I provides traffic filtering and inspection services for the campus network and […]
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Enterprise Network on GNS3 - Part 3 - Distribution and Core Layers

This is the third from the series of the articles that discuss configuration of the entire enterprise network. The article focuses on the configuration of the distribution and core switches. The distribution layer consists of two multilayer switches vEOS-DIS-I and vEOS-DIS-II. The switches are Arista vEOS version 4.17.2F Qemu appliances installed on VMware disks. Each […]
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Enterprise Network on GNS3 - Part 2 - Access Layer

This is the second from the series of the articles that discuss a complete configuration of the enterprise network. Our enterprise campus network consists of the core, distribution and access layer. This network infrastructure design is called a three-tier network model. Each layer has specific function. The access layer provides access for end users to […]
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Enterprise Network on GNS3 - Part 1 - Introduction

Several months ago I had created a simple GNS3 network topology for practicing my networking skills. What had firstly begun as a simple lab, later grew in to a real world enterprise network consisting of a campus, data center, DMZ network blocks and ISPs. During the next several weeks I added new devices into the […]
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GRE Tunnel Between Cisco and Linux

Generic Routing Encapsulation – GRE is a tunneling protocol originally developed by Cisco that encapsulates various network protocols inside virtual point-to-point tunnel. It transports multicast traffic via GRE tunnel so it allows passing of routing information between connected networks. As it lacks of security it is very often used in conjunction IP SEC VPN that on […]
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How to configure GNS3 installed on Linux to support more than 8 NIC for Qemu Instances

Recently I have read a question on GNS3 forum asking whether Qemu supports more than 8 network adapters. According to Google search, maximum number of adapters for Qemu virtual machines can be configured with a parameter #define MAX_NICS 8 in a file ./include/net/net.h under Qemu source tree. After you set desirable value you must compile and install Qemu from source. However I have noticed that changing […]
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GNS3 on Fedora Linux

Here are mu notes about installation GNS3 version on Fedora Linux. It shows the basic steps required to successfully install and configure GNS3 for VirtualBox, Qemu, IOU, and Dynamips support. Configuration of individual VirtualBox, Qemu, IOU and IOS images is not discussed. 1. GNS3 GUI and Server Installation and Configuration 1.1 Install Dependencies $ sudo yum […]
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GNS3 on Fedora

GNS3 is based on Dynamips and Dynagen (a text-based front-end for Dynamips) to create a complex virtual Cisco networks, adding many additional features and most  importantly making it easy to create, change and save your network topologies. It was also extended for Qemu virtualizer/emulator and VirtualBox support. The next steps we will show how to […]
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GNS3 Qemu Troubleshooting

Many GNS3 users use Qemu emulator to run various network OS installed on Qemu images – for example Olive, ASA, Vyatta and many others. Some users complain about not having a network connections between these devices or a console window appears and disappears  after the short time. In both cases Qemu hosts are not started […]
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