{

    "name": "Toolbox",

    "category": "guest",

    "description": "This appliance contains server side software for secondary management of network devices:\n- www (nginx) \n- ftp (vsftpd)\n- tftp (tftpd)\n- syslog (rsyslog)\n- dhcp (isc-dhcpd)\n- snmp server (snmpd + snmptrapd)",

    "vendor_name": "Ubuntu",

    "vendor_url": "https://www.ubuntu.com/",

    "product_name": "Networkers' toolbox",

    "registry_version": 3,

    "status": "stable",

    "maintainer": "Andras Dosztal",

    "maintainer_email": "developers@gns3.net",

    "symbol": "linux_guest.svg",

    "usage": "Root password: gns3",

    "docker": {

        "adapters": 1,

        "image": "adosztal/net_toolbox:latest",

        "console_type": "telnet"

    }

}

copie ce code ci-dessus dans un fichier net_toolbox.gns3a

puis tu fais comme pour les autres appliance ;-)