What is --data-length used for, and when would you apply it?

• A. It speeds up the scan
• B. It adds a payload to probes for fingerprint variability and IDS evasion
• C. It changes the target's ports
• D. It enables verbose mode

Answer: (B)

Adjusting probe payload length. This option adds a specified amount of random data to each probe’s payload, increasing the data length that the target sees. You’d use it when you want to vary the probe content to improve fingerprinting accuracy and to help evade simple IDS/IPS rules that look for fixed patterns. By altering the payload, responses can become more distinctive, aiding OS/service identification in environments with detection rules or where probes of identical length are more easily flagged. It doesn’t change ports, speed, or verbosity—it’s all about the probe’s data length and how the target and defenses react to that variation.