TCP SYN (p0f)

4:37+27:0:1460:mss*20,7:mss,sok,ts,nop,ws:df,id+:0

first seen 2026-06-14 17:27 · last seen 2026-10-31 17:18 · 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

4:37+27:0:1460:mss*20,7:mss,sok,ts,nop,ws:df,id+:0

Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 …

User-Agent claims Windows

TCP SYN initial TTL 37+27 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 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36
Observed TTL	37+27 (observed + path distance → initial)
Claimed OS	Windows
Confidence	low — single sighting of an environmental signal

low

2026-06-14

4:37+27:0:1460:mss*20,7:mss,sok,ts,nop,ws:df,id+:0

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.…

User-Agent claims Windows

TCP SYN initial TTL 37+27 indicates Unix-like

Full User-Agent	Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0
Observed TTL	37+27 (observed + path distance → initial)
Claimed OS	Windows
Confidence	low — single sighting of an environmental signal

low

2026-10-31

Last 7 days (4 observations)

Decomposed attributes

IP version	`4`
Initial TTL	`37+27`
Options length	`0`
MSS	`1460`
Window size	`mss*20`
Window scale	`7`
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
`t13d251100_b78ed14e2fd0_ab7e3b40a677`	4
`t12d490600_730fb1b0ac6a_a1e935682795`	2
`t13d191000_9dc949149365_e7c285222651`	1
`t12d4906h1_730fb1b0ac6a_22a92d800fe4`	1

HTTP request (JA4H)

fingerprint	co-occurrences
`ge11nr050000_57c5e92682a8_000000000000_000000000000`	4
`ge11nn07zhcn_ad6bb88d6320_000000000000_000000000000`	2
`ge11nn020000_3ed38b250d3d_000000000000_000000000000`	1
`ge11nn06zhcn_2d855731be57_000000000000_000000000000`	1

TCP SYN (JA4T)

fingerprint	co-occurrences
`29200_2-4-8-1-3_1460_7`	6

User-Agent

fingerprint	co-occurrences
`Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11) AppleWebKit/601.1.27 (KHTML, like Gecko) Chrome/47.0.2526.106 Safari/601.1.27`	2
`Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36`	1
`Dalvik/2.1.0 (Linux; U; Android 9.0; ZTE BA520 Build/MRA58K)`	1
`Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0`	1
`Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:125.0) Gecko/20100101 Firefox/125.0`	1
`Mozilla/5.0 (ZZ; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36`	1
`Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/608.2.11 (KHTML, like Gecko) Version/13 Safari/608.2.11`	1

Country

fingerprint	co-occurrences
`CN` · China	4
`UZ` · Uzbekistan	4

Network (ASN)

fingerprint	co-occurrences
`AS202660` · "Uzbektelekom" Joint Stock Company	4
`AS58461` · CT HangZhou IDC	2
`AS4134` · CHINANET BACKBONE	1
`AS4811` · China Telecom (Group)	1

TLS supported groups

fingerprint	co-occurrences
`11ec,11eb,11ed,001d,0017,0018,0019` Match?Exact match in Thumbprint's published controlled catalog captures: go-net/http 1.27.3, go-net/http 1.26.10.The fingerprint page shows the full measured match list. More on the catalog.	4