TCP SYN (p0f)

6:107+21:0:1378:mss*47,8:mss,nop,ws,nop,nop,sok:flow:0

first seen 2026-08-17 19:19 · last seen 2026-08-17 19:19 · JSON

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 version6
Initial TTL107+21
Options length0
MSS1378
Window sizemss*47
Window scale8
Options layoutmss,nop,ws,nop,nop,sok
Quirksflow
Payload class0

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)

fingerprintco-occurrences
t13d1515h2_8daaf6152771_a54fffd0eb611

HTTP request (JA4H)

fingerprintco-occurrences
ge20nr12enus_979a40433f82_000000000000_0000000000001

HTTP/2 frames (Akamai)

fingerprintco-occurrences
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)

fingerprintco-occurrences
64766_2-1-3-1-1-4_1378_81

User-Agent

fingerprintco-occurrences
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:153.0) Gecko/20100101 Firefox/153.01

Country

fingerprintco-occurrences
DE · Germany1

Network (ASN)

fingerprintco-occurrences
AS207781 · Marcel Menzel1

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).

fingerprintlinked observations
q13d0314h3_55b375c5d22e_1ecea7cb6ec11