How to add Cisco IOS (Dynamips Images) to GNS3

GNS3 is one of the renown and best network software simulator released in 2008. In GNS3 you can import Cisco IOS Router images and practice as much as you want.

We will explain you step by step process of How to add Cisco IOS (Dyanamips Images) to GNS3.

1. Download Cisco IOS (Dyanamips Images)
2. Importing Cisco IOS image to GNS3
3. Calculating Idle-PC

if you want to practice Cisco ASA / IOU/ IOL on eve-ng for your certification or knowledge then check below posts-

How to add Cisco IOU/IOL to Eve-ng
How to add Cisco ASAv to Eve-ng

1. Download Cisco IOS (Dynamips images) GNS3

In order run Cisco IOS image in GNS3, first we need to download the images. We have provided two links – one from Cisco Website if you have the access and encase you do not have the access to Cisco Software you can use external link to download the images. Images provided below are strictly for education purpose and are not hosted on server. We are just indexing the links find on internet for education purpose only.

You can download Cisco IOS (dynamips images) from below links.
1. Cisco Website (Cisco Access required to download images from cisco website.
2. Mega!fpxnXIKB!twpa-jzH4ReWZFq5uZENZg

2. Add Cisco IOS (Dynamips images) to GNS3

Before Importing Cisco IOS images to GNS3, I am asumsing you have already installed GNS3 and if you have not installed GNS3 you can follow below link to install and configure GNS3 step by Step process.

How to install GNS3 step by step Process.

  • Start GNS3 and Click Edit from top left bar and select Preferences.



  • Now, we have to upload the Cisco IOS images to GNS3.
    Once Preferences popup comes up, select IOS routers from Dyanamips tab.
    Now click the IOS router option it will show you the option to add new IOS router image on right side.

cisco ios images


  • Select New Image option and click Browse button. Now select the downloaded IOS image file which you want to use for your lab.

cisco images gns3


  • GNS3 supports both type of files compressed and decompressed and by default IOS files are compressed. If GNS3 asked to decompress the file, select no.


  • Click next and continue the Wizard.

  • If selected IOS belongs to an outdated device, wizard may display a warning message.In real life, using an outdated device is not recommended. Since GNS3 uses a real Cisco IOS, it also follows the same recommendation and warns us about the outdated IOS. If we are going to use this device only for CCNA exam preparation or to get some hands on experience on Cisco IOS, we can ignore this message.


  • Now wizard extracts the hardware information (platform and chassis number) form selected IOS file and lists it in next screen along with an automatically populated device name.If extracted information does not match with device, select the correct platform and chassis number from drop down. If require, you may also adjust the device name.

    Verify / adjust the information and Click Next button to continue

  • Next screen allows us set the RAM size for this device. By default wizard automatically allocates the minimum recommended memory (RAM) for device. But if require, we can adjust it to match with our specific requirement.

  • If selected IOS belongs to a modular device, next screen allows us to install the interfaces in available slots.


  • Select appropriate interfaces and click Next button.

  • Just like interfaces slots, if selected IOS belongs to a device which has WIC modules, next screen allows to install the WIC interface in WIC slots.

  • Select the desire WIC interface and click Next button

  • Next screen allows us to put a limit on CPU usage by this IOS. We should always specify this value. This value prevents a faulty or buggy IOS from consuming entire CPU cycles. Once this value is configured, GNS3 does not allow IOS from consuming CPU beyond this limit.

    3. Calculating Idle-PC

    Click Idle-PC finder button and use the suggested value in this field.

  • Click Finish button to close the wizard


And Enjoy

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