TCP SYN (p0f)

4:50+14:0:1452:mss*45,10:mss,sok,ts,nop,ws:df,id+:0

first seen 2026-06-23 16:27 · last seen 2026-07-05 13:47 · JSON

Inconsistencies

User-Agents observed with this fingerprint that contradict what it proves at the wire. all inconsistencies →

fingerprint User-Agent claims wire shows confidence seen first seen last seen

4:50+14:0:1452:mss*45,10:mss,sok,ts,nop,ws:df,id+:0

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:149…

User-Agent claims Windows

TCP SYN initial TTL 50+14 indicates Unix-like

The initial TTL is set by the sending kernel (64 on Unix-like systems, 128 on Windows) and survives NAT. But VPNs, proxies and tunnels legitimately replace the sending stack, so this check never exceeds medium confidence.

Full User-Agent	Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:149.0) Gecko/20100101 Firefox/149.0
Observed TTL	50+14 (observed + path distance → initial)
Claimed OS	Windows
Confidence	low — single sighting of an environmental signal

low

2026-06-23

Decomposed attributes

IP version	`4`
Initial TTL	`50+14`
Options length	`0`
MSS	`1452`
Window size	`mss*45`
Window scale	`10`
Options layout	`mss,sok,ts,nop,ws`
Quirks	`df,id+`
Payload class	`0`

Co-observed signals

Signals from other families seen in the same observation. A fingerprint spread thinly across many lower-layer signatures is a classic inconsistency signal.

TLS ClientHello (JA4)

fingerprint	co-occurrences
`t13d3012h2_1d37bd780c83_882d495ac381` Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.21.0, curl 8.22.0, curl 8.20.0, +6 more.The fingerprint page shows the full measured match list. More on the catalog.	1
`t13d1616h2_86a278354501_0c27189014cf` Match?Exact match in Thumbprint's published controlled catalog captures: firefox 153.0, firefox 153.0.3, firefox 152.0.6, +10 more.The fingerprint page shows the full measured match list. More on the catalog.	1

HTTP request (JA4H)

fingerprint	co-occurrences
`ge20nr06enus_7dc1fb81e529_000000000000_000000000000`	1
`ge20nr11enus_187a9385d229_000000000000_000000000000`	1

HTTP/2 frames (Akamai)

fingerprint	co-occurrences
`3:100;4:65536;2:0\|1048510465\|0\|m,s,a,p` Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.13.0, curl 8.18.0, curl 8.21.0, +7 more.The fingerprint page shows the full measured match list. More on the catalog.	1
`1:65536;2:0;4:131072;5:16384\|12517377\|3:0:0:22\|m,p,a,s` Match?Exact match in Thumbprint's published controlled catalog captures: firefox 153.0, firefox 153.0.3, firefox 154.0, +25 more.The fingerprint page shows the full measured match list. More on the catalog.	1

TCP SYN (JA4T)

fingerprint	co-occurrences
`65340_2-4-8-1-3_1452_10`	1

User-Agent

fingerprint	co-occurrences
`Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:149.0) Gecko/20100101 Firefox/149.0`	1
`Mozilla/5.0 (X11; Linux x86_64; rv:152.0) Gecko/20100101 Firefox/152.0`	1

Country

fingerprint	co-occurrences
`HU` · Hungary	1
`ES` · Spain	1

Network (ASN)

fingerprint	co-occurrences
`AS3352` · TELEFONICA DE ESPANA S.A.U.	1
`AS20845` · DIGI Tavkozlesi es Szolgaltato Kft.	1

Cross-transport links

TLS ClientHello fingerprints observed from the same client via the beacon's correlation id on the other transport (e.g. this stack over TCP ↔ that stack over QUIC).

fingerprint	linked observations
`q13d0315h3_55b375c5d22e_dc5437974b47`	1