A connectivity check determines whether a device responds when contacted. Depending on which option is selected, discovery scan times and network traffic can vary. If an IP responds, the device is created and Data collection can begin. If it does not respond, the device is not created and we move on to the next address. Please note, UDP ports are not checked as part of connectivity checks. Use the following controls to enable/disable advanced discovery connectivity check options:

Ping only. Select this option to have discovery perform a basic connectivity check using ICMP ping. Please note, the Windows operating system, both client and server, disables inbound ICMP ping by default in Windows Defender Firewall.

Ping & credential port connectivity checks. Select this option to have discovery perform a balanced discovery scan which includes good network coverage but minimizes excessive traffic or delays. If an initial ICMP ping check returns no response, the following TCP ports are checked: port 80 (http, non-SSL), port 135 (WMI), and port 443 (https). Please note, this is the default option enabled when accessing this area of the discovery scan wizard.

Ping & port connectivity checks. Select this option to likely find the most devices possible, albeit while generating more network traffic and resulting in an increased discovery scan duration. If an initial ICMP ping check returns no response, the following TCP ports are checked: 9, 21-23, 25, 80, 110, 123, 135, 137-139, 143, 443, 445, and 500. Please note, this option also allows you to specify additional port numbers to check. To do so, enable the Custom Ports checkbox, then enter port numbers in the field provided.

Regardless of the option selected, discovery stops checking ports once it receives a response. If a custom port is specified, but a different port responds first, the custom port will not be included in data collection or inventory reports. Please note, ports are scanned in sets of 10. Each set can take up to 10 seconds. Additionally, guaranteed data collection only occurs on ports 80, 143, and 443.