Which of the following is the best method of accurately identifying the services running on a victim host?

Telneting manually to each open port performs direct banner grabbing, where the actual service responds with its own identification string (e.g., SSH version, FTP banner, HTTP server header). This bypasses assumptions made by automated tools and gives the true service identity as reported by the service itself, making it the most accurate identification technique.

Port scanners identify services primarily based on port number conventions rather than actual service responses, which can be inaccurate if services run on non-standard ports.

Hit and trial guessing is not a systematic method and provides no reliable technical basis for accurately identifying services.

Vulnerability scanners probe ports to find weaknesses but are not optimized for accurate service identification and can misclassify services running on non-default ports.