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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Dynamips Compilation and Installation on Fedora Linux

This guide shows how to build  Dynamips on Fedora Linux. Dynamips x86 and x86-64 binaries compiled for Fedora can be downloaded here: Dynamips Installation – prior to 0.2.13 1. Download Dynamips Sources wget http://sourceforge.net/projects/gns-3/files/Dynamips/0.2.8-RC7-community/dynamips-0.2.8-RC7-community.source.zip/download 2. Extract Tarball tar zxvf  ./dynamips-0.2.8-RC7-community.tar.gz 3. Install Dependencies sudo yum install libpcap elfutils-libelf  elfutils-libelf-devel  libuuid libuuid-devel gcc libpcap libpcap-devel cd ./dynamips-0.2.8-RC7-community 4. Make Symbolic Link […]
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EtherChannel,VRRP, DHCP, OSPF Configuration - Cisco, Vyatta, Microcore

The tutorial shows EtherChanel, VRRP, DHCP and OSPF configuration on Cisco, Vyatta and Microcore Linux.  A campus network (look at figure 1) is created with Access and Distribution layer. Instead of Layer 2 switches in Access layer there is Cisco Router 3725  occupied with NM-16SW module in this layer and Cisco  is emulated by Dynamips. […]
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Router on a Stick Configuration - Juniper, Cisco, Vyatta

Layer 2 switch is  a network device which provides network access for hosts connected to its ports. Hosts  are grouped  in to VLANs  according to switch port configuration.  If they are hosts belonging to different VLANs it is not connectivity between hosts (http://en.wikipedia.org/wiki/Virtual_LAN) so it must be a mechanism which provides connectivity  – routing between  […]
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GNS3: How to run multiple Qemu instances in Windows

Hi, I created video in which I showed how to run multiple Qemu instances in  GNS3 installed on Windows.  There is a bug in Qemu, installed on Widows  which prevents you to run more than one Qemu instance. This video is mainly for Windows users because bug is presented only in Windows OS. Copying base […]
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Simple Compatibility test between Cisco, Vyatta and LISA

In the previous tutorials I showed how to create Vyatta and LiSA qemu image. Now, it is time play a little bit with these network devices and to make simply compatibility test between Cisco 3725, Vyatta 6.1 Core and LiSA. I created a test topology with two Vyattas, Cisco 3725 router, with NM-16SW, Cisco 7206VXR […]
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