Recognizable network signals
Operating systems choose TCP settings such as window size, maximum segment size and option order. Their combination can suggest a broad system family.
Network stack
TCP/IP fingerprint test
See the network signals your connection reveals. Start a test when you are ready.
Your result
ReadyReady to check your connection
Start the test to capture a fresh network observation.
Estimated operating system family
Not checked
Confidence—
A VPN, proxy or router can change these signals. This is an estimate, not an exact device identification.
Behind the result
Open the measurements or evidence you want to inspect.
TCP packet measurements & signature
Localtonet signatureNot checkedThe Localtonet
lts1 signature is not JA4T or p0f.Address family—
TTL—
Window size—
Classification evidence & connection matching
- Evidence will appear after the check.
What does this tell you?
Your connection can change them
A VPN, proxy, firewall or router may alter these settings. The result can describe an intermediary rather than your device.
Why is the result unavailable or inconclusive?
The collector needs to match a fresh connection to its packet metadata. Connection reuse, filtering, rate limits or several simultaneous connections can prevent a reliable match. Run the check again to request a new observation.
What do TTL, MSS and option order mean?
TTL limits how many routers a packet can pass. MSS is the largest TCP payload the sender wants to receive. TCP options negotiate features such as window scaling and timestamps. The combination is more useful than any one value.
Does this scan my device or identify me?
Your browser makes an HTTPS request; the collector observes that connection’s initial packet. It does not scan your ports or identify you by name. Public results omit the source address, source port and raw TCP timestamps.
