I need to be able to emulate a Juniper Router (JunOS) on GNS3.

I have seen that this is available as on option in the 'Node Types' list on GNS3.

Juniper Router Node in GNS3

When I try to use this to add a Juniper Router to the simulation using the above Node Type, I get an error message:

enter image description here

Please let me know how I could configure this. Detailed steps to configure this would be really helpful.

  • I think this question belongs more in the superuser section then the networkengineering question.
    – Bulki
    Mar 17, 2014 at 6:28
  • 3
    ...why the close votes? ("Tools related to network engineering" is explicitly on topic.) So I think we'd need some very clear reason to close this. Thoughts? Mar 17, 2014 at 21:01

2 Answers 2


This can be configured using VirtualBox or using Qemu. These are the steps required to setup JunOS on GNS3 using Qemu:

  1. Acquire an image of JUNOS. The image file should be with the extension .img

  2. Open GNS3 and go to Edit -> Preferences -> Qemu

  3. Make sure the settings in the General Settings section are correct. Below is a screenshot of what the Qemu settings should look like:

    QMenu Settings

  4. Click on Test Settings to check if your settings are correct

  5. Click on the JunOS tab on the same Preferences window

    • Enter any name for the identifier name
    • For the binary image, select the image you acquired in step 1
    • Select a value for the RAM. The minimum I have seen for this is 256MB. You may also leave this blank and GNS3 will assign this for you.
    • Enter the number of NICs that you want on the Juniper Router (default is 6)
    • Select the model of the NICs you want on the Juniper Router (default is e1000)

    Sample Settings for JunOS settings section:

    JunOS Settings

  6. Click Save to save the JunOS image. Close the Preferences window by clicking Apply.

  7. Now you are able drag the Juniper Router from the left panel and drop them to the topology.

Note: If you want ta add multiple Juniper routers to your topology, you have to make multiple copies of the image acquired in step 1. Then from the GNS3 program right click on every Juniper router -> Configure -> In the JunOS Image: setting, specify the path of a different image file for each instance.

Helpful Links:

  1. NiL - How to run JunOS inside of GNS3

  2. Waleed Khan - JUNOS on GNS3 through Qemu


Haven't used it for quite some time but last time this tutorial worked for me:


Also take a look at http://www.juniper.net/de/de/dm/firefly/ You can download a virtual Juniper SRX (for VMWARE, Linux KVM, Virtualbox) which you can connect to GNS3 via the "cloud" symbol.

  • 2
    please give some explenation in your answers and do not only use links.
    – Bulki
    Mar 17, 2014 at 6:27
  • I don't think that it is essential for the answer to "copy" the contents of the howto into the answer just to have more text here and not "only links". BTW: I used this tutorial ~ 1 month ago, it worked fine for me (Ubuntu 13.10, GNS3 0.8.6)
    – Sebastian
    Mar 18, 2014 at 10:18
  • @Sebastian looks like it would have been helpful since the url is giving a 500 now ;) heres a waybackmachine link if anyone needs it: web.archive.org/web/20121201015822/http://blog.gns3.net/2009/10/…
    – iainlbc
    Feb 3, 2015 at 0:05

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