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How to fix GNS3 Errors Connecting to Server 127.0.0.1

Posted in Articles, GNS3, Networking2 years ago • Written by Shais33 Comments

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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Shais

I'm a network and Information Security instructor. Here is my online pictorial notebook. I would like to write and share my experience through this website for computer enthusiasts and technology geeks.

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33 Comments so far. Feel free to join this conversation.

  1. vidhun sahayarajMarch 8, 2015 at 12:47 pm - Reply

    Hi

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

    • Shais
      ShaisMarch 8, 2015 at 4:48 pm - Reply

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

  2. Niaz MohammadMarch 26, 2015 at 7:34 pm - Reply

    very good teching

  3. kararMarch 26, 2015 at 7:35 pm - Reply

    This is an Superb solution for this problam!

  4. adnanMarch 26, 2015 at 7:35 pm - Reply

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

  5. sakhisafariMarch 26, 2015 at 7:36 pm - Reply

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

  6. AlJune 21, 2015 at 6:26 pm - Reply

    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. NamSeptember 19, 2015 at 2:06 pm - Reply

    i’m tried but it’s not change

  8. EmmanuelOctober 30, 2015 at 3:01 am - Reply

    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

    • Shais
      ShaisOctober 30, 2015 at 11:39 am - Reply

      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. NileshNovember 4, 2015 at 8:36 pm - Reply

    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!

    • Shais
      ShaisNovember 4, 2015 at 11:40 pm - Reply

      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. NileshNovember 5, 2015 at 10:42 pm - Reply

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

    • Shais
      ShaisNovember 6, 2015 at 11:17 am - Reply

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

  11. dading1234December 17, 2015 at 4:27 pm - Reply

    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

    • Shais
      ShaisDecember 21, 2015 at 12:20 am - Reply

      Thanks, your article is great.

  12. RajaJanuary 13, 2016 at 10:18 pm - Reply

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

    Thank You mate ..

    cheers,

    Raja.

    • Shais
      ShaisJanuary 13, 2016 at 11:36 pm - Reply

      Your welcome Raja,
      Thanks for comment

  13. HasbiFebruary 15, 2016 at 1:04 pm - Reply

    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. DeviPrasadFebruary 15, 2016 at 2:51 pm - Reply

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

  15. Jhon FredyFebruary 24, 2016 at 1:38 am - Reply

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

    • Shais
      ShaisFebruary 24, 2016 at 6:51 pm - Reply

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

  16. ScottMarch 14, 2016 at 12:17 am - Reply

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

  17. Kyle L.March 20, 2016 at 10:56 am - Reply

    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.

    • Shais
      ShaisMarch 20, 2016 at 6:53 pm - Reply

      Thanks Kyle L.

  18. Bhanu Pratap MahatoMarch 30, 2016 at 4:18 pm - Reply

    Solved.
    Added GNS3 folder in AVG Antivirus exception list.

  19. modarnApril 20, 2016 at 4:11 pm - Reply

    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. ydoucareApril 22, 2016 at 10:46 am - Reply

    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. KeyboardbangerMay 28, 2016 at 3:15 pm - Reply

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

  22. DanielJuly 29, 2016 at 12:58 am - Reply

    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. SCAugust 10, 2016 at 9:43 pm - Reply

    Thanks – it worked

  24. whoeAugust 26, 2016 at 8:20 pm - Reply

    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. kadernjoyaDecember 23, 2016 at 12:22 pm - Reply

    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

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