TCP SYN (JA4T)

65520_2-4-8-1-3_1260_7

first seen 2026-06-29 23:12 · last seen 2026-10-23 22:45 · JSON

Distinct clients per day (last 30 days, peak 2/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 window	`65520`
Option kinds	`2-4-8-1-3`
MSS	`1260`
Window scale	`7`

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
`t13d3013h2_1d37bd780c83_8537cf56674e` Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.18.0.The fingerprint page shows the full measured match list. More on the catalog.	7
`t13d1011h1_61a7ad8aa9b6_3fcd1a44f3e3`	6
`t13d1714h2_5b57614c22b0_53a6d0ab1c42`	1

HTTP request (JA4H)

fingerprint	co-occurrences
`ge20nn030000_ff50983941c1_000000000000_000000000000`	3
`ge11nn040000_cf1edba2959c_000000000000_000000000000`	2
`ge20nn020000_5594a17e7e7e_000000000000_000000000000` Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.7.1, curl 8.5.0, curl 8.13.0, +11 more.The fingerprint page shows the full measured match list. More on the catalog.	2
`ge20nn030000_bf75ddd0bb29_000000000000_000000000000`	2
`ge11nn05enus_20ffb2d95d94_000000000000_000000000000`	2
`ge20nr13enus_44e1f6d71293_000000000000_000000000000`	1
`ge11nr040000_cf1edba2959c_000000000000_000000000000`	1
`ge11nr05enus_20ffb2d95d94_000000000000_000000000000`	1

HTTP/2 frames (Akamai)

fingerprint	co-occurrences
`3:100;4:65536;2:0\|1048510465\|0\|m,s,a,p` Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.13.0, curl 8.18.0, curl 8.21.0, +8 more.The fingerprint page shows the full measured match list. More on the catalog.	7
`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 155.0.1, +32 more.The fingerprint page shows the full measured match list. More on the catalog.	1

TCP SYN (p0f)

fingerprint	co-occurrences
`4:51+13:0:1260:mss*52,7:mss,sok,ts,nop,ws:df,id+:0`	6
`4:57+7:0:1260:mss*52,7:mss,sok,ts,nop,ws:df,id+:0`	6
`4:45+19:0:1260:mss*52,7:mss,sok,ts,nop,ws:df,id+:0`	1
`4:52+12:0:1260:mss*52,7:mss,sok,ts,nop,ws:df,id+:0`	1

User-Agent

fingerprint	co-occurrences
`curl/8.14.1`	6
`Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; SEOJuice-SearchBot/1.0; +https://seojuice.io/bot`	6
`Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:134.0) Gecko/20100101 Firefox/134.0`	1
`Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36`	1

Country

fingerprint	co-occurrences
`US` · United States	8
`NL` · Netherlands	5
`NO` · Norway	1

Network (ASN)

fingerprint	co-occurrences
`AS3257` · GTT Communications Inc.	6
`AS39351` · 31173 Services AB	5
`AS50304` · Blix Solutions AS	1
`AS52485` · networksdelmanana.com	1
`AS265645` · HOSTINGFOREX S.A.	1

TLS supported groups

fingerprint	co-occurrences
`11ec,001d,0017,001e,0018,0019,0100,0101` Match?Exact match in Thumbprint's published controlled catalog captures: python-httpx 0.28.1, python-requests 2.34.2, curl 8.23.0, +4 more.The fingerprint page shows the full measured match list. More on the catalog.	2

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).

fingerprint	linked observations
`q13d0315h3_55b375c5d22e_dc5437974b47`	1