marionnet.org — a virtual network laboratory

Frequently asked questions

The software

What kind of computer does Marionnet run on?

On a GNU/Linux computer with a 64-bit x86 processor, not ARM: the packages and the precompiled archive are only published for that architecture. Marionnet does not run on Windows or macOS. Each virtual machine is a Linux kernel running as an ordinary process of the host (User Mode Linux), and that requires a Linux host. The distributions on which installation has been checked, from Debian 11 and Ubuntu 20.04 to Fedora 42, Rocky Linux 10 and openSUSE Leap 16.0, are listed at the top of the full installation guide.

As for resources, the Debian 13 image for the machines takes about 5 GB of disk once installed. By default, a Debian 13 machine gets 192 MB of memory and a router 24 MB, so a network of four machines and two routers needs less than 1 GB.

What about Windows or macOS?

Marionnet is then used inside a Linux virtual machine (under VirtualBox or VMware, for example), where it stays smooth and pleasant to use. User Mode Linux needs no hardware support for virtualisation: each machine of the network is just an ordinary process of the guest Linux system, so there is no nested virtualisation to enable, and the two levels of virtualisation can be stacked without any noticeable effect on performance. The emulated systems are also lightweight, as the home page points out: by default, a Debian 13 machine gets 192 MB of memory, a Debian 7 (wheezy) machine 96 MB and a router 24 MB. On top of what its own desktop needs, the Linux virtual machine therefore only requires about 1 GB for a network of four machines and two routers. Note, however, that this virtual machine must itself be 64-bit x86, which rules out Macs with Apple processors (M1 and later): a Linux virtual machine on them is ARM, and emulating an x86 processor there would be far too slow.

How does it differ from Packet Tracer?

Marionnet’s machines and routers are emulated: each one boots a real Linux kernel and a real GNU/Linux system, with its commands and services, which students administer as they would a physical machine. Cisco’s Packet Tracer, like Boson’s NetSim, simulates the devices instead: it imitates their behaviour. In Marionnet, only hubs, switches and cables are simulated, by the VDE tools. The Project page explains the distinction in more detail.

Are there .deb and .rpm packages?

Yes, since 2026: a signed apt repository for Debian, Ubuntu and derivatives, a signed dnf / zypper repository for Fedora, the RHEL family and openSUSE, and a precompiled archive for the other distributions. The quick installation guide consists of commands to copy and paste. Note that on a host of the RHEL 10 family (Rocky Linux and AlmaLinux 10), the router is not available yet: its image is 32-bit, and the 32-bit kernel cannot be installed there. A Debian 13 machine with several network cards can still play that role, configured by hand.

Does Marionnet exist in my language?

The interface matches the language of your desktop session. It exists in English (en), and translated into German (de), Spanish (es), Esperanto (eo), French (fr), Greek (el), Italian (it), Portuguese (pt), Brazilian Portuguese (pt_BR), Romanian (ro), Russian (ru), Slovak (sk) and Turkish (tr). Your language is missing? Translating needs no programming skill; contribute it on Launchpad.

Do my old projects still open?

Yes. A .mar project saved by an older version can still be opened. If the kernel or the distribution it names is no longer published, Marionnet replaces it with an equivalent, then lists in a window what it has changed. There is one exception: a machine whose disk state was saved in the project. That state only applies to its original image, so if the image is gone, the machine is dropped from the opened project, and the window says so (What’s new in 2026 gives the details).

Also, an old project saved by this version is converted to the new format, which an earlier version of Marionnet can no longer open. If some computers have not been updated yet, keep a copy of the file before saving it. Finally, to get an old environment back exactly (a guest distribution withdrawn since, for instance), you can still install an old version.

The virtual machines

What is the root password on machines and routers?

root. The published images also have an ordinary account, student, whose password is student.

How do I configure a router? Is it Quagga only?

Marionnet’s router is a small GNU/Linux machine running Quagga. Its port 0 starts with the address 192.168.1.254/24. You can change it in the router’s dialog window (Port 0 IPv4 address) or, like the addresses of the other ports, in the Interfaces tab, below the network map.

For the rest, there are two ways:

Like the graphical applications of the machines, these terminals depend on privilege block (a): if they do not open, see the question on graphical applications.

How do my virtual machines reach the Internet?

By placing an exit device on the network map, from the “planet” button of the palette (the column of component icons on the left): Gateway (no privilege at all), NAT bridge (a private network behind address translation, with DHCP, DNS and, optionally, IPv6) or LAN bridge (the machines appear on the host’s real local network). There is no longer any Ethernet bridge to set up by hand; What’s new in 2026 compares the three components.

The NAT bridge and the LAN bridge change the host’s network. So the first time one of them is started, Marionnet asks for the user’s sudo password. For a room of students who are not allowed to use sudo, the administrator can grant the NAT bridge in advance: see section 3.3 of the full installation guide.

Graphical applications of the virtual machines do not open

An xterm or a wireshark started in a virtual machine is displayed on the host’s screen, through an interface Marionnet creates for that purpose (a “ghost tap”). If nothing opens, the most common reason is that privilege block (a) has not been granted on this computer. This block is the base of Marionnet’s sudo rule, the part that lets it create its network interfaces on the host; the machine’s administrator (or the student, on their own laptop) grants it once, after installation: see sections 3.2 and 6 of the full installation guide.

Routers have no graphical applications; to watch the traffic there, use tcpdump.

How do I share files between the host and the virtual machines?

This is built in. Each machine and each router sees, under /mnt/hostfs, a real host directory: what is written there on one side can be read on the other, without going through the network. On the host side, that directory lies in Marionnet’s temporary working directory and is named after the component:

/tmp/marionnet-<n>.dir/<project>/hostfs/<machine name>/

For instance, to copy myapp into every machine of the current project, on a host where only one Marionnet session is running:

for d in /tmp/marionnet-*.dir/*/hostfs/*/; do
  cp myapp "$d"
done

then, in each machine, cp /mnt/hostfs/myapp .

Two precautions, however. This directory is temporary: copy any files you want to keep to another location before closing the project. And do not touch the files Marionnet puts there: any file whose name starts with marionnet-relay is run when the machine boots, and the boot journals are written there.

With the control channel, the exact path can be queried, here for the machine m1:

mrnctl -q '.hostfs' rc-get m1

Another question, a problem

Ask it, or report the problem you ran into, on Launchpad: the Contact page says where to write and what to include.