What does the --ttl option influence in Nmap scanning?

What does the --ttl option influence in Nmap scanning?

• A. It sets the IP TTL field
• B. It changes the DNS resolver timeout
• C. It toggles verbose output
• D. It selects the scan timing template

Answer: (A)

The --ttl option controls the value placed in the IP header’s TTL (time-to-live) field for probes that Nmap sends. TTL is decremented by each router along the path, and when it reaches zero the packet is discarded. By setting a specific TTL, you influence how many hops your probes can traverse, which can affect reachability and the responses you observe. TTL values also matter for OS fingerprinting because different operating systems use characteristic default TTLs for their packets, so adjusting TTL can change the fingerprints Nmap collects. This option isn’t about DNS resolver timeouts, verbose output, or scan timing templates.

The --ttl option controls the value placed in the IP header’s TTL (time-to-live) field for probes that Nmap sends. TTL is decremented by each router along the path, and when it reaches zero the packet is discarded. By setting a specific TTL, you influence how many hops your probes can traverse, which can affect reachability and the responses you observe. TTL values also matter for OS fingerprinting because different operating systems use characteristic default TTLs for their packets, so adjusting TTL can change the fingerprints Nmap collects. This option isn’t about DNS resolver timeouts, verbose output, or scan timing templates.