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New post, Infix in GNS3 a mini HowTo
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
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‎_posts/2026-03-12-infix-in-gns3.md‎

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---
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title: "Infix in GNS3"
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description: "Build and test networks virtually, no hardware required"
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author: troglobit
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date: 2026-03-12 09:00:00 +0100
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categories: [howto]
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tags: [gns3, networking, virtual, beginner]
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image:
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path: /assets/img/gns3.png
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alt: GNS3 — Graphical Network Simulator
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show_in_post: false
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---
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[GNS3][] is a graphical network simulator that lets you build, cable up,
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and run virtual network topologies on your desktop. It is widely used
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for learning, lab work, and testing interoperability between different
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vendors — and Infix is available directly from the [GNS3 Marketplace][mktroot],
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making it easy to add to any project.
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This post walks you through getting Infix running in GNS3, from
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installation to your first working topology.
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> The examples here use the **x86_64** Infix build. GNS3 runs its
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> device emulation via Qemu, which requires a Linux host — see the
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> [server setup](#server-setup) section below if your organisation runs
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> macOS or Windows.
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{: .prompt-info }
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### Installing GNS3
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GNS3 is best installed on a [Debian][]-based Linux distribution such as
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[Ubuntu][] or [Linux Mint][]. Add the official PPA and install:
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```bash
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$ sudo add-apt-repository ppa:gns3/ppa
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...
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$ sudo apt update
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...
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$ sudo apt install gns3-gui gns3-server
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...
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```
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> During installation you will be asked whether non-root users should be
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> allowed to run Qemu and use Wireshark. Answer **yes** to both,
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> otherwise GNS3 will require `sudo` every time.
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{: .prompt-tip }
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For Windows and macOS, download the all-in-one installer from
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[gns3.com][GNS3]. It bundles the GNS3 VM — a small Linux virtual
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machine that handles the Qemu side — see the [server setup](#server-setup)
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section for more on how this works.
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### Adding the Infix Appliance
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Infix is available directly from the [GNS3 Marketplace][mkt]. For a full
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walk-through of the install flow, see the [GNS3 documentation][mktguide].
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The steps below are Infix-specific:
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1. Open GNS3 and go to **File → New Template**
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2. Select **Install an appliance from the GNS3 server** and click **Next**
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3. Search for **Infix** in the appliance list and select it
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4. When asked for a disk image, click **Download** to fetch it
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directly, or point it to a `.qcow2` file you have already downloaded
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from the [Infix releases page][rels]
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5. Click **Finish** — Infix now appears under **Routers** in the device panel
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### Building a Topology
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Creating a lab is drag, drop, and cable. As a first example we will
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build a simple gateway setup: a PC connected to the internet via an
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Infix router.
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1. Open or create a GNS3 project (**File → New blank project**)
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2. From the **Routers** panel, drag an **Infix** node onto the canvas
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3. From the **End devices** panel, drag a **PC** node onto the canvas
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4. From the **Network devices** panel, drag a **Cloud** node — this
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represents your host machine's internet connection
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5. Use the **Add a link** tool (cable icon) to wire them up:
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- Cloud → `eth0` on Infix (WAN)
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- `eth1` on Infix → PC (LAN)
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6. Start all nodes with **Edit → Start All Nodes**
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![GNS3 canvas showing an Infix router between an Internet cloud and a PC](/assets/img/gns3-screenshot.png)
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_**Figure 1:** A simple gateway topology — Internet cloud, Infix router, and a PC, all wired up on the GNS3 canvas._
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> Each Infix node has **10 Ethernet interfaces** (`eth0`–`eth9`) by
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> default, plenty for routing, switching, or both within the same node.
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{: .prompt-info }
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Once the nodes are running, right-click the Infix node and choose
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**Console** to open a terminal. From there the workflow is identical
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to real hardware: `cli` to enter the Infix CLI, `configure` to make
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changes, and `copy running-config startup-config` to save them.
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For more in-depth examples and multi-router topologies, see Jon-Olov's
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[OSPF Unnumbered Interfaces][ospf] post — a six-router ring built and
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verified entirely in GNS3.
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### Server Setup
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GNS3 has a split client/server architecture. The **GUI** handles the
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canvas and your interaction; the **server** (`gns3server`) manages the
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Qemu processes that actually run the devices. On Linux these run on the
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same machine with no extra configuration needed.
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On **macOS and Windows** the all-in-one installer includes the **GNS3
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VM** — a small Linux virtual machine that acts as the server. The GNS3
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GUI connects to it automatically, and Infix runs inside it. This works
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well for individual use.
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Organisations running **macOS across the board** often find it more
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practical to set up a dedicated Linux server and point all GNS3 clients
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at it — this is exactly the setup we have helped customers with:
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1. On a [Debian][]/[Ubuntu][]/[Linux Mint][] machine, install and start
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the server:
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```bash
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$ sudo apt install gns3-server
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$ gns3server
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```
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2. On each Mac, open GNS3 and go to **GNS3 → Preferences → Server →
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Remote servers** and add the Linux machine's IP address and port
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(default `3080`)
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All Qemu emulation runs on the Linux server while each user works from
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their GNS3 GUI on their Mac. The Infix appliance only needs to be
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imported once, on the server side.
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> The server must be **x86_64 Linux** — Infix ships an `x86_64` build
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> for exactly this purpose. There is no native macOS or Windows Infix
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> build.
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{: .prompt-warning }
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### Where to Go Next
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With Infix running in GNS3 you have the full feature set available —
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routing, switching, containers, firewall, WireGuard — all without any
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physical hardware. A few posts to continue with:
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- [Getting Started with Infix][gs] — the Qemu command-line workflow if
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you prefer working without a GUI
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- [OSPF Unnumbered Interfaces][ospf] — a multi-router topology built
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and verified entirely in GNS3
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- [Zone-Based Firewall][zbf] — set up a firewall between zones in a
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virtual topology
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- [Full documentation][docs] — the complete Infix user guide, including
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the [virtual environments][virt] section
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[GNS3]: https://gns3.com/
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[mktroot]: https://gns3.com/marketplace/
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[mkt]: https://gns3.com/marketplace/appliances/infix
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[ppa]: https://docs.gns3.com/docs/getting-started/installation/linux/
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[mktguide]: https://docs.gns3.com/docs/using-gns3/beginners/install-from-marketplace/
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[rels]: https://github.com/kernelkit/infix/releases
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[ospf]: /posts/ospf-unnumbered-infix/
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[gs]: /posts/getting-started/
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[zbf]: /posts/zone-based-firewall/
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[docs]: https://www.kernelkit.org/infix/
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[virt]: https://www.kernelkit.org/infix/latest/virtual/
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[Debian]: https://www.debian.org/
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[Ubuntu]: https://ubuntu.com/
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[Linux Mint]: https://linuxmint.com/

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