TCP OS Spoofing (Anti TCP/OS Fingerprinting)

Some websites detect proxies by comparing your browser's reported OS with the OS fingerprint leaking from TCP/IP behavior. TCP OS Spoofing aligns these two signals to reduce proxy detection.

TCP OS Spoofing is available from the Premium plan and above.

What is TCP/OS Fingerprinting?

Every operating system handles TCP/IP slightly differently — different window sizes, TTL values, MSS, timestamps, and TCP options. Anti-bot systems inspect these low-level signals to infer what OS is actually making the connection.

Your browser says Windows 10 (User-Agent).
But your proxy server runs Linux — and its TCP signature looks like Linux.
The mismatch is flagged as suspicious.

Why OS Spoofing matters

Most proxy servers run Linux. If you use a Windows browser profile through a Linux proxy, the TCP/OS mismatch can trigger detection. OS Spoofing rewrites the proxy's TCP/IP signature to match your browser profile's OS.

When to enable it

You use Windows-based browser profiles (e.g. in Multilogin, AdsPower, GoLogin).
Sites show "Proxy/VPN detected" or OS inconsistency warnings.
You're testing on sites that check TCP/OS fingerprints.

Supported OS fingerprints

Windows
Android
Linux (default)
iOS
macOS

How to configure

Go to General Settings → Proxy Setting → Per-Port settings.

Per port — select the OS for a single port.
Multi-port rule — apply the same OS spoof to a range of ports (e.g. 4001–4050 → Windows).

Match the spoofed OS to your browser profile's OS. If your browser profile is Windows, spoof Windows.

How to verify

BrowserLeaks — check IP and environment leaks.
Incolumitas Proxy Detect — proxy/VPN checks.
WITCH by valdikss — advanced TCP/IP tests.

Limitations

Some ISPs, carrier-grade NAT, firewalls, or DPI systems may normalize TCP options, overriding the spoofed signature.
Minor throughput/latency overhead due to packet inspection and rewriting.
If tests still show Linux: try a different ISP/APN/ASN, or avoid extra VPN layers.

FAQ

Does this change my User-Agent?

No. Your browser's User-Agent stays the same. OS Spoofing only adjusts the TCP/IP signature at the proxy layer.

What OS should I choose?

Choose the OS that matches your browser profile. Most users pick Windows for desktop profiles.

Is Android device supported?

Using an actual Android phone as the proxy device is supported. Choosing Android as the TCP/IP fingerprint is also supported — useful when using Android browser profiles or emulators.

What plan is required?

TCP OS Spoofing is available from the Premium plan.

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