TCP SYN (p0f)

4:43+21:0:1460:mss*44,10:mss,sok,ts,nop,ws::0

first seen 2026-07-28 12:31 · last seen 2026-08-25 03:46 · 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 version4
Initial TTL43+21
Options length0
MSS1460
Window sizemss*44
Window scale10
Options layoutmss,sok,ts,nop,ws
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
t13d1712h1_ab0a1bf427ad_8e6e362c5eac190

HTTP request (JA4H)

fingerprintco-occurrences
ge11nn10engb_ec5486a7d5a7_000000000000_000000000000182
ge11nn050000_be0d0b335e46_000000000000_0000000000005
ge20nn08engb_c4bf040e0aa1_000000000000_0000000000003

HTTP/2 frames (Akamai)

fingerprintco-occurrences
1:4096;2:0;4:65535;5:16384;3:100;6:65536|16777216|0|m,a,s,p Match?Exact match in Thumbprint's published controlled catalog captures: python-httpx 0.28.1.The fingerprint page shows the full measured match list. More on the catalog.3

TCP SYN (JA4T)

fingerprintco-occurrences
64240_2-4-8-1-3_1460_10190

User-Agent

fingerprintco-occurrences
uk-nhs-data/0.0 (internal fraud-research)190

Country

fingerprintco-occurrences
GB · United Kingdom190

Network (ASN)

fingerprintco-occurrences
AS8468 · ENTANET International Limited190