Go to Help > About to see important details about External Scanners and Scanner Appliances. In order to protect your network from external and internal threats, scanners must be able to access target hosts. Be sure that your network permits access to the scanners to be used.
External Scanners for perimeter scanning are located at Security Operations Centers (SOCs). External scanners must be able to send probes to target hosts on your network perimeter during scan/map processing. IP addresses for the external scanners at the SOC associated with your account/location appear on the About page (Help > About). Depending on your network, it may be necessary to add the scanner IPs to your list of trusted IPs, so that the service can send probes to target hosts.
Scanner Appliances for internal scanning may be installed inside your corporate Intranet. Scanner appliances in your account must be able to send probes to target hosts on your internal network during scan/map processing. Also, the scanner appliances must be able to contact certain URLS on port 443 at the SOC appropriate for your account/location. These URLs appear on the About page (Help > About).