TCP SYN (p0f)

4:109+19:0:1460:65535,8:mss,nop,ws,nop,nop,sok:df,id+,ecn:0

first seen 2026-07-31 05:18 · last seen 2026-07-31 05:18 · 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

4:109+19:0:1460:65535,8:mss,nop,ws,nop,nop,sok:df,id+,ecn:0

Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.…

User-Agent claims Linux

TCP SYN initial TTL 109+19 indicates Windows

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 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36
Observed TTL	109+19 (observed + path distance → initial)
Claimed OS	Linux
Confidence	low — single sighting of an environmental signal

low

2026-07-31

Decomposed attributes

IP version	`4`
Initial TTL	`109+19`
Options length	`0`
MSS	`1460`
Window size	`65535`
Window scale	`8`
Options layout	`mss,nop,ws,nop,nop,sok`
Quirks	`df,id+,ecn`
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
`t13d1812h1_85036bcba153_b26ce05bbdd6`	1

HTTP request (JA4H)

fingerprint	co-occurrences
`ge11nn10enus_d249fef7a17c_000000000000_000000000000`	1

TCP SYN (JA4T)

fingerprint	co-occurrences
`65535_2-1-3-1-1-4_1460_8`	1

User-Agent

fingerprint	co-occurrences
`Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36`	1

Country

fingerprint	co-occurrences
`DE` · Germany	1

Network (ASN)

fingerprint	co-occurrences
`AS8560` · IONOS SE	1