gns3 help

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  • Author
    • #8733
      The New LT72884

      I am having an interesting issue with gns3. Im hoping someone has some exp with this software.

      Here is my simple setup:

      ROUTER1 has ip of on fa0/0 facing private side. I have a cloud device hooked up to the router with vmnet2 as its card.

      The issue is, i can get it to ping from backtrack5 in vmpalyer, but as soon as i run a simple

      nmap -sP

      the results come back positive and says 1 live host. i try to ping again and all communication has stopped working. If i power cycle the router, it restores communication so it seems to be an internal gns3 issue.


    • #53908

      What kind of router and config did you create? you just mention private site means you are doing any NAT or any security.

      Make sure there is not nothing that as soon detect the scan shut you down.

      Try to do two thing: when you get the time out after the nmap try to change the IP address and see if it works or try to change the mac address of your card and IP and see if it works.

      If it works then your router is blocking you otherwise would be your gns3

    • #53909
      The New LT72884

      I have no security on the 7200 router. basic basic configs. No nat or pat. Just a host to the fa0/0 and thats it haha

      Here is the config
      fa 0/0 ip add
      no shut

      Here is a vid i made showing what is happening.

      If the vid does not work, what is going on is that ping from router to host is good. From host to router is good. Nmap to router is good. i try to ping again and it kills the communication. also, certain basic nmap commands will cause the same issue.


      EDIT. Im trying out above, i did not ignore your advice, just trying it out and getting results. thanks

      Ok, after changing ip and mac, no go for ping. so it looks as if gns3 is getting hosed after nmap. so what is nmap doing to it ahaha

    • #53910

      GNS3 aside, I noticed that you are using BT5R2 with Nmap 5.61TEST4.

      BT5R2 and Nmap 5.61TEST4 are both pretty old (2012), you might want to consider upgrading.

      If I get time I’ll try this out, I’m also curious to find out where the problem is.

    • #53911
      The New LT72884

      After talking to gns3 support and admins, it turns out that there is an issue with gns3 loosing connectivity with cloud devices. If you delete the cable and re-add it, the communication starts up again, however, maybe the outdated nmap is causing something in gns3 to freak out???

      im not sure but i get a solid resolution, besides deleting the cable, i will let you all know.

      I can update nmap and see if it changes. thanks for the tip.

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