TCP SYN (p0f)

4:48+16:0:1390:65535,12:mss,sok,ts,nop,ws:df,id+:0

first seen 2026-07-10 17:13 · last seen 2026-10-13 06:28 · JSON

Distinct clients per day (last 30 days, peak 5/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 TTL48+16
Options length0
MSS1390
Window size65535
Window scale12
Options layoutmss,sok,ts,nop,ws
Quirksdf,id+
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
t13d1011h2_61a7ad8aa9b6_3fcd1a44f3e3 Match?Exact match in Thumbprint's published controlled catalog captures: rust-reqwest 0.12.28.The fingerprint page shows the full measured match list. More on the catalog.4
t13d1713h2_5b57614c22b0_02c8e53ee3983
t13d1712h2_5b57614c22b0_ef7df7f74e482
t13d1712h2_5b57614c22b0_d5fe2c511efa1

HTTP request (JA4H)

fingerprintco-occurrences
ge20nr040000_ac162d8a7b0c_000000000000_0000000000006
ge20nr050000_a36a3d5685e0_000000000000_0000000000002
ge20nn050000_a36a3d5685e0_000000000000_0000000000002

HTTP/2 frames (Akamai)

fingerprintco-occurrences
2:0;1:4096;8:0;3:1024;4:1048576|25100289|0|a,p,m,s6
2:0;4:2097152;5:16384;6:16384|5177345|0|m,s,a,p Match?Exact match in Thumbprint's published controlled catalog captures: rust-reqwest 0.12.28, rust-reqwest 0.13.5, rust-reqwest 0.13.4, +4 more.The fingerprint page shows the full measured match list. More on the catalog.4

TCP SYN (JA4T)

fingerprintco-occurrences
65535_2-4-8-1-3_1390_1210

User-Agent

fingerprintco-occurrences
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; GPTBot/1.4; +https://openai.com/gptbot)7
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36; compatible; OAI-SearchBot/1.4; robots.txt; +https://openai.com/searchbot3

Country

fingerprintco-occurrences
US · United States10

Network (ASN)

fingerprintco-occurrences
AS8075 · Microsoft Corporation10