TCP SYN (p0f)

6:52+12:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:0

first seen 2026-06-26 03:05 · last seen 2026-08-26 19:58 · 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

6:52+12:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:0

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:154…

User-Agent claims Windows

TCP SYN initial TTL 52+12 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:154.0) Gecko/20100101 Firefox/154.0
Observed TTL	52+12 (observed + path distance → initial)
Claimed OS	Windows
Confidence	low — single sighting of an environmental signal

low

2026-08-26

Distinct clients per day (last 30 days, peak 1/day)

Distinct clients are counted by IP-hash per complete UTC day — unlike observation counts this is insensitive to one chatty client, but NAT merges clients and address rotation splits them.

Decomposed attributes

IP version	`6`
Initial TTL	`52+12`
Options length	`0`
MSS	`1440`
Window size	`mss*30`
Window scale	`10`
Options layout	`mss,sok,ts,nop,ws`
Quirks	`flow`
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
`t13d491100_834380eab35e_d41ae481755e`	2
`t13d1716h2_5b57614c22b0_ca3c9f312770`	2

HTTP request (JA4H)

fingerprint	co-occurrences
`ge11nn050000_ec06583e3464_000000000000_000000000000`	1
`ge11nn050000_212a08913770_000000000000_000000000000`	1
`ge20nr10enus_b3034183f430_000000000000_000000000000` Match?Exact match in Thumbprint's published controlled catalog captures: firefox 153.0, firefox 153.0.3, firefox 154.0, +21 more.The fingerprint page shows the full measured match list. More on the catalog.	1
`ge20nn11enus_3901d4197baf_000000000000_000000000000` Match?Exact match in Thumbprint's published controlled catalog captures: firefox 154.0, firefox 152.0.5, firefox 153.0.1, +3 more.The fingerprint page shows the full measured match list. More on the catalog.	1

HTTP/2 frames (Akamai)

fingerprint	co-occurrences
`1:65536;2:0;4:131072;5:16384\|12517377\|3:0:0:42\|m,p,a,s` Match?Exact match in Thumbprint's published controlled catalog captures: firefox 154.0, firefox 152.0.5, firefox 152.0.1, +3 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
`43200_2-4-8-1-3_1440_10`	3

User-Agent

fingerprint	co-occurrences
`wget/http3check.net`	2
`Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:154.0) Gecko/20100101 Firefox/154.0`	2

Country

fingerprint	co-occurrences
`US` · United States	4

Network (ASN)

fingerprint	co-occurrences
`AS20473` · The Constant Company, LLC	4