How to fix GNS3 Errors Connecting to Server 127.0.0.1

In GNS3 Network Simulator, when we drag and drop some devices like Router, an error issued. The error is ” Could not connect to 127.0.0.1 on port 8000: [WinError 10061] No connection could be made because the target machine actively refused it “.

Connecting to Server 127.0.0.1
Connecting to Server 127.0.0.1

It is not happened always but some time, maybe in the first start of GNS3 or sometime else refused by Anti viruses or Firewall software.

How to Fix GNS3 Errors
How to Fix GNS3 Errors

Unfortunately it is not only on Windows Operating system but I saw this error in Linux also.

How to fix GNS3 Errors on Windows?

So to fix the problem in Windows system, just run the GNS3 as Administrator and continue your work. Now it must work correctly. If it’s not solved your GNS3 problems, just let us know and find out how to fix GNS3 errors

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36 Comments
  1. vidhun sahayaraj says

    Hi

    I tried as run as administrator, but I am facing same problem

    1. Shais
      Shais says

      Hi
      Once clear and install the latest GNS3 v1.2.3.

  2. Niaz Mohammad says

    very good teching

  3. karar says

    This is an Superb solution for this problam!

  4. adnan says

    good for those who need to fix gns3 errors. I need IOS Images

  5. sakhisafari says

    This is very good website, it solve this GNS3 problam.
    thank you

  6. Al says

    Hi ,
    just upgraded to ‘Running GNS3 version 1.3.7.dev1 on Windows (64-bit)’, but since installation I get the Subject message. I have tried disabling the firewall and A/Virus (windows f/w turned off), I have checked the kaspersky F/W and it shows port 8000 is ‘active’. I have also tried changing server ports to other ports vice 8000 and also tried running GNS3 as admin but none of this has worked. When I had v1.2.3 loaded it all worked as advertised. All I have done is re-installed over the top of the previous version and have now deleted the installed version and wiped with an powerful uninstaller and re-installed….to no avail. Still getting the subject message. When I drop in router I get the following..’ Error while creating project: Can’t connect to server http://127.0.0.1:8000‘ which is kind of expected, but just trying to give full details

  7. Nam says

    i’m tried but it’s not change

  8. Emmanuel says

    I install the latest GNS3 each time i tried to run a Router by dragging i received the error below. I really need help.
    Server error from 127.0.0.1:8000: ESW1: Lost communication with 127.0.0.1:50315 :[WinError 64] The specified network name is no longer available, Dynamips process running: True

    1. Shais
      Shais says

      The current version of GNS3 is 1.4.0b4 and fixed lots of GNS3 errors. Once try to install it.
      If it doesn’t work, test another IOS and set pretty enough RAM for router ios.

  9. Nilesh says

    I am getting issue.
    “Server error from 127.0.0.1:8000: ESW1: Lost communication with 127.0.0.1:50315 :[WinError 64] The specified network name is no longer available, Dynamips process running: True”

    Please help!

    1. Shais
      Shais says

      The current version of GNS3 is 1.4.0b4 and fixed lots of GNS3 errors. Once try to install it. If it doesn’t work, test another IOS and set pretty enough RAM for router ios.

      I’m not pretty sure about this error, but once turn off AV and Windows firewall.

  10. Nilesh says

    I have also tried this (GNS3 is 1.4.0b4) new version also but showing same error.

    1. Shais
      Shais says

      It is relevant to your system. Try to test with another system if it is possible.

  11. dading1234 says

    I have tried 0.8.7&1.3.11,both have the problem Server error from 127.0.0.1:8000: ESW1: Lost communication with 127.0.0.1:50315 :[WinError 64] The specified network name is no longer available, Dynamips process running: True”. i have tried to change the system but also dont work

    1. Shais
      Shais says

      Thanks, your article is great.

  12. Raja says

    Simple but very effective…. Its working and the problem solved.

    Thank You mate ..

    cheers,

    Raja.

    1. Shais
      Shais says

      Your welcome Raja,
      Thanks for comment

  13. Hasbi says

    Please help me, how to slove it : Server error from 127.0.0.1:8000: Mikrotik Web: Attachment (hostonly) already configured on adapter 1. Please set it to ‘Not attached’ to allow GNS3 to use it. thank’s

  14. DeviPrasad says

    turn off anti virus and firewall in your PC & run as administrator will solve the problem

  15. Jhon Fredy says

    To fix it, just run the windowas task manager, then go to detils and look for a GNS3 procces, closed it. That´s all.

    1. Shais
      Shais says

      It just close the current process, you must run it again.

  16. Scott says

    gns3 1.4.4 nothing works. av and firewall turned off, run as admin, 127.0.0.1:8000 actively refused.

  17. Kyle L. says

    Just fixed this problem a few minutes ago on my windows machine.
    1) I ran netstat -a to see what ports are being listened on. I had a number of ports for 127.0.0.1 in the listening state (in this case 8307)
    2) I changed the local port under Edit –>Preferences –> Server; where there is the host binding option.
    3) Make sure it’s under 127.0.0.1 or any other interface you choose
    4) Change the port to one of the ports listed as listening in your netstat -a output from the cmd window.
    5) Ensure your path to gns3.exe is correct and it should work.

    1. Shais
      Shais says

      Thanks Kyle L.

  18. Bhanu Pratap Mahato says

    Solved.
    Added GNS3 folder in AVG Antivirus exception list.

  19. modarn says

    the problem on port 127.0.0.1 in gns3 4
    i cannot fix it even i delete the avg and i do start with admin way and i did to change the the port of 127.0.0.1 on edit and it does not work

  20. ydoucare says

    So… Download the GNS.VM and run it on vmware … that will work, here are the links:

    https://github.com/GNS3/gns3-gui/releases

    once you´ve installed it the VPCS device will work, in order to run the IOS… better get the image and run it on your PC instead, specify the directory you have the image on by going under preferences> Dynamips> IOS images.. and voila!! you are welcome.

  21. Keyboardbanger says

    Thanks for the tip but GNS3 keeps crashing on my machine, on Windows.

  22. Daniel says

    I currently use AVG Antivirus and resolved this issue permanently by adding an exception for Dynamips.exe.

    Disable AVG, then:
    Open AVG, Options, Advance Settings, Exceptions, (Browse to GNS3, Dynamips) add dynamips.exe.

    You can then enable AVG.

  23. SC says

    Thanks – it worked

  24. whoe says

    is here anybody?why this damn problem is still **** me….i have no Antivirus,firewall down,win10 64bit,god damn….i have done everything….anybody …save me….

  25. kadernjoya says

    iam learning cisco associate ihave face the same pb mine was not working because of the antivirus AVG when i UNINSTALL IT GNS3 start working normally

  26. Chuck says

    Can anyone help me please. Same problem, How can i run as Administrator ?

    1. Shais
      Shais says

      Right click the GNS3 and run as administrator.

  27. Del says

    I had this same problem. It was my Anti-virus program (AVG)

    Uninstalled it and now it fine. Reinstalling now I know the cause and will create a few rules.

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