TCP SYN (JA4T)

65535_2-4-8-1-3_1390_12

first seen 2026-06-30 01:35 · last seen 2026-09-15 21:44 · JSON

Last 7 days (193 observations)

Distinct clients per day (last 30 days, peak 16/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

TCP window65535
Option kinds2-4-8-1-3
MSS1390
Window scale12

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.851

HTTP request (JA4H)

fingerprintco-occurrences
ge20nr050000_a36a3d5685e0_000000000000_000000000000513
ge20nn050000_a36a3d5685e0_000000000000_000000000000338

HTTP/2 frames (Akamai)

fingerprintco-occurrences
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 0.13.4, rust-reqwest 0.12.28, rust-hyper 1.11.0, +3 more.The fingerprint page shows the full measured match list. More on the catalog.851

TCP SYN (p0f)

fingerprintco-occurrences
4:44+20:0:1390:65535,12:mss,sok,ts,nop,ws:df,id+:0420
4:45+19:0:1390:65535,12:mss,sok,ts,nop,ws:df,id+:0414
4:43+21:0:1390:65535,12:mss,sok,ts,nop,ws:df,id+:010
4:48+16:0:1390:65535,12:mss,sok,ts,nop,ws:df,id+:04
4:42+22:0:1390:65535,12:mss,sok,ts,nop,ws:df,id+:03

User-Agent

fingerprintco-occurrences
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; +https://openai.com/searchbot400
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/searchbot247
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; GPTBot/1.4; +https://openai.com/gptbot)204

Country

fingerprintco-occurrences
US · United States851

Network (ASN)

fingerprintco-occurrences
AS8075 · Microsoft Corporation851