Which scanning option allows users to define specific ports?

The ability to define specific ports for scanning is critical for targeted assessments and can help in identifying vulnerabilities on particular services. User Defined scanning allows users to customize the scan by specifying a list of ports that they want the scan to focus on. This approach is particularly useful in scenarios where certain applications or services are known to run on non-standard ports, or when compliance requirements dictate scanning only specific ports to assess security posture.

By using the User Defined option, it provides flexibility and precision, enabling users to concentrate on the most relevant services that might be running in their environment. It can also optimize scanning time and resources by avoiding unnecessary checks on ports that are not in use or are irrelevant to the current assessment.

In contrast, the other options like Common Ports, All Ports, and Default Ports do not provide the level of customization that User Defined offers. Common Ports typically scans a pre-defined list of frequently used ports, All Ports scans every possible port, which may not be practical, while Default Ports will target the ports that are configured by default in the scanning tool, limiting the customization based on the user's needs.