GNS3 Errors Troubleshooting

You may run into GNS3 errors from time to time.  This post covers some of the more common GNS3 errors and how to fix them.

GNS3 is a free, open source network simulation tool you can load on your PC to run Cisco router simulations. When installing and running GNS3 you will inevitably run into errors that prohibit the tool from performing properly.

The following GNS3 errors occur:
Error: 205-VM R0: unable to add binding for slot 0/0

  • routers must be turned off before making connections between them
  • make sure you have the correct slots installed on the router
    • right click the router
    • select configure
    • select the router - R1
    • select the tab "Slots"
    • add modules to the slot - which modules can I add?

Error: 206-unable to create generic ethernet NIO

  • you need admin or root privileges to access the network interfaces
  • make the gns3 user an admin
  • or modify the Menu and add gksu before each command to execute GNS3 (gksu --preserve /usr/local/bin/gns3)

Error: 209-unable to start VM instance ‘ghost-c3660-jk9s-mz.123-15.T14.bin.unpacked-localhost.ghost’

  • almost always caused by incorrect image name
  • check .net file against the entire image path
  • if ghost version doesn't exist than remove ghost=true from .net file

No image for platform c2691

  • add an IOS image for each router platform
    • click Edit in the GNS3 menu
    • select IOS images and Hypervisors
    • browse for your image file
    • specify the platform
    • Save It!

Console terminal window opens and closes right away

Dynamips Test – Failed to start Dynamips

Can’t start Dynamips on port 7200

My computer is extremely slow when I start a GNS3 lab

Could not connect to server


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