Archives For cloonix

The Domain Name System (DNS) is a fundamental Internet technology. Network emulators like Cloonix offer a way for researchers and students to experiment with the DNS protocol and with the various open-source implementations of DNS, such as BIND.

In this post, I will install Cloonix from the Github source code repository. I will run the Cloonix DNS demo script to create a simple DNS scenario and then run some experiments with DNS. Along the way, I will demonstrate some of the new Cloonix version 33 features.

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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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The Cloonix development team recently released a major update to the Cloonix network simulator.

Cloonix version 28 makes major changes to the infrastructure of Cloonix. It changes the installation procedure, the location of Cloonix files on your computer, and the names of the commands used to start and administer Cloonix.


Cloonix version 28 also makes changes to the features available to users. It adds support for multiple Cloonix servers running on the same machine, and standardizes and documents the new interface types used to connect virtual machines to each other.

Read the rest of this post for more details about what’s new in Cloonix v28.

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When using open-source network simulators that use KVM as a virtualization tool, each node in the network simulation is actually a KVM virtual machine so the maximum supported number of nodes in a network simulation is the same as the maximum number of KVM virtual machines that can run on the host computer.

Unfortunately, there seems to be no single authoritative statement about the maximum number of KVM virtual machines that can run on a host computer. Most information I could find about KVM limits does not publish absolute limits but, instead, recommends best practices.

In this post, I will synthesize the information available from many different sources into a single recommendation for the maximum number of KVM-based nodes that can run in an open-source network simulator running on a single host computer.

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The Cloonix development team released an update to Cloonix version 26 in May 2015. An important addition in version 26 is a greatly expanded and improved Cloonix user guide.


The new version also changes the user interface, adds a new LAN type, and eliminates the t2t device. It also includes updated guest virtual machines.

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The Cloonix open-source network simulator uses the Spice remote desktop system to provide a virtual desktop connection to quest virtual machines that run a graphical user interface, such as Microsoft Windows or a Linux desktop environment.

To use a graphical desktop user interface on a guest VM, we access the VM using the Spice desktop console.

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To run a program that uses a graphical user interface on a guest virtual machine running in the cloonix open-source network simulator, log into the guest VM from the host computer using SSH and forward the X11 display. Then, any X11 program you run on the guest VM using that SSH session, such as Wireshark, will display its X windows on the host computer.

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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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The cloonix project provides a variety of root filesystems for use in the cloonix network simulator. These root filesystem only have the most basic software packages installed and will not support advanced network configuration (with the exception of router filesystems such as openwrt).

To create a network simulation that runs real-world networking software, we need to install new software on the root filesystems we will use in cloonix. In this example, we chose to start with the Debian jessie root filesystem and we will install some networking software and a desktop environment.

We will also show how to save the upgraded root filesystem for future use as either a static or non-static root filesystem.

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The cloonix development team recently updated the cloonix network simulator to version 24. This post describes the changes in cloonix v24 compared to cloonix v19, which we reviewed in a previous post.

Cloonix open-source network simulator on Linux

Version 24 simplifies the setup of guest virtual machines, improves the link performance emulation tool, and adds new interface types designed to improve packet throughput performance. Users familiar with the cloonix graph GUI will have no problems using this new version, but shell scripts with cloonix ctrl commands may need to be updated, because the ctrl CLI has changed.

Please read on to see a detailed description of the changes.

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Install Cloonix v24

May 18, 2014

The Cloonix open-source network simulator was recently updated to version 24. The last time I used Cloonix, it was at version 19 (see my review of Cloonix and my using the Cloonix graph interface posts). Compared to version 19, only a few details of the installation procedure have changed — the list of package dependencies is different compared to v19.

The Cloonix v24 installation procedure is documented in the README file that comes with the source code. For my own reference, I will describe the procedure, along with some additional information, in this post.

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Cloonix v21 runs in Knoppix

February 28, 2013

The Cloonix development team recently released Cloonix version 21. The new version includes some significant improvements, such as support for Cisco software images (via Dynamips) and support for 32-bit architectures. The Cloonix developers also added a large library of prepared filesystems including new, lightweight versions of popular linux filesystems, such as debian, ubuntu and fedora, and open-source routers, such as Vyatta and openWRT.

Cloonix in 32-bit Knoppix desktop

In version 21, Cloonix now runs on 32-bit and 64-bit versions of Ubuntu, Debian, and Fedora. Cloonix provides pre-compiled packages for those systems.

Cloonix will also compile and run on other Linux distributions. We will show how to compile and run Cloonix v21 on Knoppix Linux and discuss the new features in v21 that make Cloonix even more interesting as an open-source network simulator.

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