HK blog

 For a basic usage of GNS3, some configuration is needed after you install "gns3" and "gns3-server" in your Manjaro or Arch Linux machine. Required group permissions for the linux user are "wireshark" (for using the live capture of packets) and "libvirt" (for using virtualization capabilities, required for example for NAT, as mentioned in the previous blog entry). Commands to execute are : sudo usermod -aG wireshark user sudo usermod -aG libvirt user replace "user" with your username for the Linux session. 

Problem: You can't add a NAT connection to your GNS3 simulation, and you get the error : "ERROR template_manager:226 Error while creating node from template: NAT interface virbr0 is missing, please install libvirt" Steps to resolve: 1- Create a file named /tmp/default.xml 2- Paste this content and save: <network>   <name>default</name>   <bridge name="virbr0"/>   <forward mode="nat"/>   <ip address="192.168.123.1" netmask="255.255.255.0">     <dhcp>       <range start="192.168.123.2" end="192.168.123.254"/>     </dhcp>   </ip> </network> 3- Execute the following commands in your shell : virsh net-define /tmp/default.xml sudo virsh net-start default sudo virsh net-autostart default