Archives For quagga

VirtualBox is an open-source virtual machine manager and hypervisor that may also be used as a network emulator. In addition to creating and managing individual virtual machines, VirtualBox can connect virtual machines together to emulate a network of computers and network appliances such as routers or servers. VirtualBox works on the major computing platforms: Windows, MacOS, and Linux.

In this post, I offer a step-by-step tutorial showing how to use the VirtualBox graphical user interface to set up a network of six devices: three routers and three PCs. This tutorial will utilize some of the advanced functions supported by VirtualBox and provide you with the skills to set up a network of virtual machines on your own personal computer.

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This post lists the commands required on each node to build a network of three Ubuntu Linux routers. Each router is connected to the other two routers and is running quagga. Each router is also connected to a PC running Ubuntu Linux.


I use this network configuration to evaluate network emulators and open-source networking software in a simple scenario. Readers may find these commands useful in building their own configuration scripts.

I provide “copy and paste” commands so the network can be configured quickly.

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The Cloonix network simulator has been updated to version 29, which adds the ability to save network simulation topologies and node configurations to a directory.

Users may save a network topology and all node configurations to a directory of their choice. They may also load saved topologies into Cloonix so they can restore a network scenario they previously created. The save function of Cloonix v29 supports copy-on-write filesystems and also allows users to save the full filesystems of nodes, if they wish.

This post will work through a detailed tutorial showing how to save, load, and re-save topologies and node configurations using the Cloonix GUI or command-line interface.

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GNS3 1.3 will create and manage VirtualBox virtual machine linked clones from within the GNS3 user interface. This simplifies the process of setting up VirtualBox virtual machines in GNS3, which makes GNS3 easier to use for studying the operation of open-source routers, switches, and hosts in network simulation scenarios.


In this post, I will show how to set up and use VirtualBox linked clones in your GNS3 simulation scenarios and work through a detailed tutorial.

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As we work through this tutorial, we will learn how to use the cloonix graph interface to build a simulation scenario that includes two small IPv6 networks connected to each other by two routers via static routes. We will also learn how cloonix saves network topologies and guest virtual machine root filesystems.

Cloonix IPv6 linux network simulation

Linux IPv6 network simulation running on the cloonix open-source network simulator

The cloonix open-source network simulator uses KVM virtual machines in the simulated network so, in this tutorial, we will demonstrate real Linux router and host configuration procedures.

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Previously, we installed the CORE Network Emulator from source code and installed the network services used by CORE. Now, we want to run a simulated networking scenario and modify the configuration of the quagga routing daemon on one or more virtual routers.

To do this, we open a shell to the node and start the vtysh shell so we can use the quagga command-line interface. But, the quagga vtysh shell starts with a mostly blank screen displaying the text “(END)”.

vtysh shows blank screen with (END) text

vtysh shows blank screen with (END) text

We have to enter the “q” key to get back to the vtysh command prompt so we can enter the required configuration command. Every time we enter a vtysh configuration command we see the blank screen with “(END)” again.

Read on to learn how to fix this annoying problem.

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