nerdexam
EC-Council

312-50V13 · Question #433

Harris is attempting to identify the OS running on his target machine. He inspected the initial TTL in the IP header and the related TCP window size and obtained the following results: TTL: 64 Window

The correct answer is D. Linux OS. Based on a TTL of 64 and a TCP window size of 5840, the target machine is likely running Linux OS, as these values are characteristic of its network stack implementation.

Submitted by kev92· Mar 6, 2026Footprinting and Reconnaissance

Question

Harris is attempting to identify the OS running on his target machine. He inspected the initial TTL in the IP header and the related TCP window size and obtained the following results: TTL: 64 Window Size: 5840 What is the OS running on the target machine?

Options

  • ASolaris OS
  • BWindows OS
  • CMac OS
  • DLinux OS

How the community answered

(46 responses)
  • A
    7% (3)
  • B
    2% (1)
  • C
    2% (1)
  • D
    89% (41)

Why each option

Based on a TTL of 64 and a TCP window size of 5840, the target machine is likely running Linux OS, as these values are characteristic of its network stack implementation.

ASolaris OS

Solaris OS typically uses an initial TTL of 255.

BWindows OS

Windows OS commonly uses an initial TTL of 128.

CMac OS

Mac OS (macOS) usually has an initial TTL of 64, but its TCP window size often differs from 5840.

DLinux OSCorrect

A common initial TTL (Time To Live) value for Linux operating systems is 64, and a TCP window size of 5840 bytes is also a signature often associated with Linux kernels. These specific values, especially when seen together during network reconnaissance, are strong indicators used in OS fingerprinting to identify a Linux-based system.

Concept tested: OS fingerprinting (TTL and TCP window size)

Topics

#OS fingerprinting#TTL#TCP window size#Linux OS

Community Discussion

No community discussion yet for this question.

Full 312-50V13 Practice