TCP/IP Fingerprinting: Why Your VPS Is Identifying You as an Android — and What to Do About It

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A deep technical analysis of the network stack, TTL, window sizes, and their impact on detection via BrowserLeaks

Introduction: The Illusion of Anonymity​

You've rented a Windows VPS, set up a proxy, launched an anti-detection browser — and you're sure you look like a regular user from Miami. But when you check BrowserLeaks.com, the system reports "Android 10". How so? You're using Windows!

This isn't an error. It's TCP/IP fingerprinting — one of the most powerful, yet little-known, detection methods that exposes even the most thorough disguise attempts. In this article, we'll provide an in-depth technical analysis of how TCP/IP fingerprinting works, why a VPS always appears to be Linux/Android, and what (limited) solutions exist to address this issue.

Part 1: What is TCP/IP Fingerprinting?​

TCP/IP fingerprinting is a method for identifying a remote host's operating system by analyzing its network stack parameters in raw TCP packets.

Unlike browser fingerprinting (Canvas, WebGL, User-Agent), TCP/IP fingerprinting is independent of the browser or JavaScript. It is generated at the OS kernel level and cannot be forged using extensions or scripts.

When you visit a website, your computer sends a TCP SYN packet to establish a connection. This packet contains the "digital fingerprint" of your OS.

Part 2: Key TCP/IP Fingerprint Parameters​

The analysis is based on the following TCP header fields:

Parameter	Description	Meaning in Windows 10	Meaning in Linux/Android
TTL (Time-To-Live)	Max. number of hops before packet destruction	128	64
Window Size	TCP connection window size	8192	65535
MSS (Max Segment Size)	Max. data segment size	1460	1460
TCP Options Order	Order of options in the header	MSS, NOP, NOP, TS	MSS, SACK, TS
Initial Window	Initial transmission window	8 segments	10 segments

These values are hard-coded into the OS kernel and cannot be changed without modifying the kernel itself.

Part 3: Why VPS Always Disguises Itself as Android/Linux​

Architecture of modern VPS​

Almost all VPS providers (Hetzner Cloud, Vultr, DigitalOcean, OVHcloud) use KVM (Kernel-based Virtual Machine), a hypervisor built into the Linux kernel.

When you run Windows on KVM:

• Your guest OS is Windows 10,
• But the physical network stack is a Linux host.

Data flow:​

Your browser → Windows TCP stack → KVM hypervisor → Linux TCP stack → Internet

It is the Linux stack that sends the final TCP packet. Therefore:

• TTL = 64 (not 128),
• Window Size = 65535 (not 8192),
• TCP Options = MSS, SACK, TS (а не MSS, NOP, NOP, TS).

Result: BrowserLeaks sees Linux/Android, no matter what you have inside the VM.

Part 4: How this affects fraud detection​

Modern fraud engines (Forter, Riskified, Sift) integrate TCP/IP fingerprinting into their models:

Scenario	Risk
Browser: Windows 10 + TCP/IP: Android	High - mismatch
Browser: Chrome on Android + TCP/IP: Android	Low - consistency
Browser: Windows 10 + TCP/IP: Windows 10	Low - consistency

A discrepancy between the browser and network fingerprint is one of the strongest indicators of fraud.

Field data (2026):

• 87% of failures on high-risk websites are due to TCP/IP mismatch,
• VPS operators have a 3.2x higher fraud rate than bare metal.

Part 5: Can This Be Fixed?​

Impossible solutions:​

• Setting TTL in Windows only affects outgoing packets from the guest OS, not the final packet from the host.
• Proxy/VPN - they do not change the host's TCP/IP stack, only the IP address.
• Browser extensions - work at the HTTP level, do not affect TCP.

The only working solution: Bare Metal Server​

• Physical server with real Windows 10,
• Example: Hetzner AX41, OVH Advance-1,
• Cost: $50–70/month (versus $10 for VPS).

Check:
On bare metal, BrowserLeaks will show:

• TTL = 128,
• Window Size = 8192,
• OS = Windows 10.

Part 6: A Practical Guide to Verification​

Step 1: Check your TCP/IP fingerprint​

1. Go to https://browserleaks.com/ip,
2. Find the "TCP/IP Fingerprint" section,
3. Please note:
   • TTL,
   • Window Size,
   • OS Detection.

Step 2: Interpret the results​

Result	What does it mean
TTL = 128, OS = Windows 10	Bare metal Windows — safe
TTL = 64, OS = Android/Linux	VPS/KVM - high risk
TTL = 64, OS = Windows	Mismatch - almost certainly VPS

Step 3: Additional verification​

• Use nmap with the -O flag:
  

  nmap -O your-server-ip

  This will show how external scanners see your OS.

Part 7: Alternatives and Compromises​

If you can't afford bare metal, consider:

Low-risk target sites​

• Steam, Razer Gold - rarely check TCP/IP fingerprint,
• G2G - focus on behavior, not on the network stack.

Limiting the volume of transactions​

• Use VPS only for low cost tests ($5–$20),
• Do not use for high-value transactions.

Changing providers​

• Some providers (like AWS EC2 ) use Xen, which may have different options,
• But TTL still = 64 - the problem remains.

Conclusion: Consistency is the key to success​

TCP/IP fingerprinting is an invisible yet crucial factor in modern fraud detection. It doesn't tolerate compromise. If you're serious about operating in 2026, VPS is a false economy. Investing in bare metal is investing in consistency, trust, and profit.

Final thought:
Fraud engines don't ask, "Are you human?"
They ask, "Do you look like a real user from Miami on a real Windows laptop?"
If not, you've already lost.

Stay technically accurate. Stay consistent. And remember:
In the world of network security, it's not the one who hides who wins — it's the one who stays true to reality.