TCP SYN (p0f)

4:48+16:0:1255:mss*44,7:mss,sok,ts,nop,ws:df,id+:0

first seen 2026-09-23 10:20 · last seen 2026-09-23 11:04 · 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

4:48+16:0:1255:mss*44,7:mss,sok,ts,nop,ws:df,id+:0

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleW…

User-Agent claims Windows

TCP SYN initial TTL 48+16 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) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36
Observed TTL	48+16 (observed + path distance → initial)
Claimed OS	Windows
Confidence	medium — repeated co-occurrence, but initial TTL is environmental — capped at medium

medium

2026-09-23

Decomposed attributes

IP version	`4`
Initial TTL	`48+16`
Options length	`0`
MSS	`1255`
Window size	`mss*44`
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
`t13d1516h2_8daaf6152771_d8a2da3f94cd` Match?Exact match in Thumbprint's published controlled catalog captures: chromium 149.0.7827.102, chrome 149.0.7827.102, chrome 149.0.7827.156, +25 more.The fingerprint page shows the full measured match list. More on the catalog.	3
`t13d1517h2_8daaf6152771_dcad5a053991`	1

HTTP request (JA4H)

fingerprint	co-occurrences
`ge20nr14dede_273cb9519eb0_000000000000_000000000000`	2
`ge20nn15enus_0a06f3270101_000000000000_000000000000`	1
`ge20nn15dede_0a06f3270101_000000000000_000000000000`	1

HTTP/2 frames (Akamai)

fingerprint	co-occurrences
`1:65536;2:0;4:6291456;6:262144\|15663105\|1:1:0:256\|m,a,s,p` Match?Exact match in Thumbprint's published controlled catalog captures: chromium 131.0.6778.33, chromium 151.0.7922.34, chrome 151.0.7922.137, +60 more.The fingerprint page shows the full measured match list. More on the catalog.	1
`1:65536;2:0;4:6291456;6:262144;43658:3836518077\|15663105\|1:1:0:220\|m,a,s,p`	1
`1:65536;2:0;4:6291456;6:262144;51962:1302629678\|15663105\|3:1:0:220\|m,a,s,p`	1
`1:65536;2:0;4:6291456;6:262144;51914:1168031193\|15663105\|1:1:0:256\|m,a,s,p`	1

TCP SYN (JA4T)

fingerprint	co-occurrences
`64240_2-4-8-1-3_1255_7`	4

User-Agent

fingerprint	co-occurrences
`Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36`	3
`Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/153.0.0.0 Safari/537.36`	1

Country

fingerprint	co-occurrences
`NL` · Netherlands	3
`DE` · Germany	1

Network (ASN)

fingerprint	co-occurrences
`AS43350` · NForce Entertainment B.V.	3
`AS62651` · Strong Technology, LLC.	1

fingerprint	co-occurrences
`1:65536;2:0;4:6291456;6:262144\|15663105\|1:1:0:256\|m,a,s,p` Match?Exact match in Thumbprint's published controlled catalog captures: chromium 131.0.6778.33, chromium 151.0.7922.34, chrome 151.0.7922.137, +60 more.The fingerprint page shows the full measured match list. More on the catalog.	1
`1:65536;2:0;4:6291456;6:262144;43658:3836518077\|15663105\|1:1:0:220\|m,a,s,p`	1
`1:65536;2:0;4:6291456;6:262144;51962:1302629678\|15663105\|3:1:0:220\|m,a,s,p`	1
`1:65536;2:0;4:6291456;6:262144;51914:1168031193\|15663105\|1:1:0:256\|m,a,s,p`	1