MyLeaks TCP fingerprint
JavaScript required
Algorithm: myleaks-tcp-v1
TCP fingerprint test
Observe initial TCP SYN characteristics
Inspect selected characteristics of the initial IPv4 TCP SYN that reached MyLeaks and see how the current network path may have influenced them.
Live result
Current passive TCP observation
JavaScript is required to establish and correlate the qualifying HTTPS connection.
Not observed means that no usable TCP result was available for this connection.
Initial SYN summary
JavaScript required
Technical details
- Availability reason
- JavaScript required
- Canonical
- JavaScript required
- Raw TCP window
- JavaScript required
- MSS
- JavaScript required
- Window scale
- JavaScript required
- SACK permitted
- JavaScript required
- Timestamp option
- JavaScript required
- TCP Fast Open
- JavaScript required
- ECE/CWR state
- JavaScript required
- IPv4 DF
- JavaScript required
- TCP option order
- JavaScript required
- Duplicate known options
- JavaScript required
- Observed TTL
- JavaScript required
- Estimated initial TTL
- JavaScript required
- Estimated hops
- JavaScript required
JavaScript is required to run the live TCP test.
What this test measures
MyLeaks observes selected characteristics of the initial IPv4 TCP SYN, including window, MSS, window scale, option presence and order, ECN flags, and IPv4 DF.
How it works
The test reads the initial TCP connection characteristics and builds a versioned summary from stable fields. See Methodology for calculation details.
What the result means
The result summarizes selected initial SYN characteristics received by MyLeaks. It is MyLeaks-defined and is not JA4T. The hash excludes the connection tuple, observed TTL, estimated initial TTL, and estimated hop count.
Limitations
- NAT, a VPN, proxy or middleware, firewalls, and other network devices may alter what reaches MyLeaks.
- Observed TTL is factual for the received packet; initial TTL and hop count are labeled estimates and excluded from the fingerprint hash.
- Shared characteristics are common.
- The result describes the current connection path, not the exact operating system or device.