What operating system would respond to the command 'C:\> nmap -sW 10.10.145.65'?

What operating system would respond to the command 'C:\> nmap -sW 10.10.145.65'?

• A. Mac OS X
• B. Windows XP
• C. FreeBSD
• D. Windows 95

Answer: (C)

Window scan with Nmap relies on how a host’s TCP window size is handled in replies. The -sW option probes the target and uses the TCP window size to help decide whether ports are open or closed. This behavior depends on the target’s TCP/IP stack, and BSD-based stacks like FreeBSD expose the kind of TCP window behavior that Nmap uses for this probe. Older or different Windows TCP stacks (such as Windows 95/XP) don’t respond to these probes in the same reliable way, so they’re not the typical environment where this scan type yields the expected results. Among the given systems, FreeBSD is the classic example where the window-size probing works as intended, which is why it would respond to that command in a way aligned with Nmap’s -sW scan.

Window scan with Nmap relies on how a host’s TCP window size is handled in replies. The -sW option probes the target and uses the TCP window size to help decide whether ports are open or closed. This behavior depends on the target’s TCP/IP stack, and BSD-based stacks like FreeBSD expose the kind of TCP window behavior that Nmap uses for this probe. Older or different Windows TCP stacks (such as Windows 95/XP) don’t respond to these probes in the same reliable way, so they’re not the typical environment where this scan type yields the expected results. Among the given systems, FreeBSD is the classic example where the window-size probing works as intended, which is why it would respond to that command in a way aligned with Nmap’s -sW scan.