TCP SYN (JA4T)

64800_2-4-8-1-3_1440_10

first seen 2026-06-29 23:14 · last seen 2026-09-16 01:09 · JSON

Last 7 days (99 observations)

Distinct clients per day (last 30 days, peak 14/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 window64800
Option kinds2-4-8-1-3
MSS1440
Window scale10

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
t13d3112h1_1d947a95fc68_b72e173852fa424
t13d3112h1_1d947a95fc68_fa269c3d986d117
t12d290700_fc2078a0b8c0_8c06664c3ac519
t13d1516h2_8daaf6152771_806a8c22fdea Match?Exact match in Thumbprint's published controlled catalog captures: chrome 150.0.7871.187, chrome 151.0.7922.137, chromium 151.0.7922.34, +24 more.The fingerprint page shows the full measured match list. More on the catalog.8
t13d1617h2_86a278354501_3e9721a6796e5
t13d131100_f57a46bbacb6_e5728521abd45
t13d1517h2_8daaf6152771_3cbfd9057e0d Match?Exact match in Thumbprint's published controlled catalog captures: firefox 154.0, firefox 154.0.1, firefox 155.0.1, +1 more.The fingerprint page shows the full measured match list. More on the catalog.4
t13d1713h1_ab0a1bf427ad_ecd0401ec68b 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
t13d1516h2_8daaf6152771_0c27189014cf Match?Exact match in Thumbprint's published controlled catalog captures: firefox 154.0, firefox 155.0.1, firefox 154.0.1.The fingerprint page shows the full measured match list. More on the catalog.3
t13d1515h2_8daaf6152771_a54fffd0eb612

HTTP request (JA4H)

fingerprintco-occurrences
ge11nn07cscz_62ad33df7c0a_000000000000_000000000000329
ge11nn07cscz_d4021d63333c_000000000000_00000000000071
ge11nn06cscz_fcadf6bdaa82_000000000000_00000000000058
ge11nn06cscz_f604b96915d0_000000000000_00000000000054
ge11nn06cscz_a9e98b5c162a_000000000000_00000000000029
ge11nn05en00_61812dc1cc58_000000000000_0000000000008
ge11nn040000_bfa5a9b89dd6_000000000000_0000000000007
ge20nr12enus_54b4638ab28b_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: chrome 150.0.7871.187, chrome 151.0.7922.137, edge 151.0.4129.93, +36 more.The fingerprint page shows the full measured match list. More on the catalog.6
ge11nr050000_3658ef221638_000000000000_0000000000005
ge20nr11enus_187a9385d229_000000000000_0000000000004

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.10
1:65536;2:0;4:6291456;6:262144|15663105|1:1:0:220|m,a,s,p Match?Exact match in Thumbprint's published controlled catalog captures: chrome 150.0.7871.187, chromium 149.0.7827.102, chrome 149.0.7827.102, +59 more.The fingerprint page shows the full measured match list. More on the catalog.5
1:65536;2:0;4:131072;5:16384|12517377|3:0:0:42|m,p,a,s Match?Exact match in Thumbprint's published controlled catalog captures: firefox 154.0, firefox 152.0.5, firefox 152.0.1, +3 more.The fingerprint page shows the full measured match list. More on the catalog.5
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.2
1:65536;2:0;4:6291456;6:262144|15663105|1:1:0:256|m,a,s,p Match?Exact match in Thumbprint's published controlled catalog captures: chromium 131.0.6778.33, chromium 151.0.7922.34, chrome 151.0.7922.137, +43 more.The fingerprint page shows the full measured match list. More on the catalog.2
1:65536;2:0;4:6291456;6:262144|15663105|3:1:0:220|m,a,s,p Match?Exact match in Thumbprint's published controlled catalog captures: chromium 151.0.7922.34, chromium 147.0.7727.15, chromium 145.0.7632.6, +21 more.The fingerprint page shows the full measured match list. More on the catalog.2
1:65536;2:0;4:131072;5:16384|12517377|7:0:0:42|m,p,a,s1
1:65536;2:0;4:131072;5:16384|12517377|5:0:0:42|m,p,a,s1
1:65536;2:0;4:131072;5:16384|12517377|11:0:0:42|m,p,a,s1
1:65536;2:0;4:131072;5:16384|12517377|9:0:0:22|m,p,a,s1

TCP SYN (p0f)

fingerprintco-occurrences
6:44+20:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:0205
6:42+22:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:0129
6:43+21:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:073
6:46+18:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:055
6:45+19:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:043
6:47+17:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:040
6:49+15:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:027
6:48+16:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:07
6:41+23:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:06
6:50+14:0:1440:mss*45,10:mss,sok,ts,nop,ws:flow:06

User-Agent

fingerprintco-occurrences
Mozilla/5.0 (compatible; SeznamBot/4.0; +https://o-seznam.cz/napoveda/vyhledavani/en/seznambot-crawler/)541
Mozilla/5.0 (compatible; MJ12bot/v1.4.8; http://mj12bot.com/)19
Mozilla/5.0 (X11; Linux x86_64; rv:152.0) Gecko/20100101 Firefox/152.011
Mozilla/5.0 (X11; Linux x86_64; rv:153.0) Gecko/20100101 Firefox/153.06
Mozilla/5.0 (compatible; DomainExtractor/1.0)5
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/150.0.0.0 Safari/537.364
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.364
Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.02
DataFoundationResearch/0.1 (+contact@example.com)2
csint.dev/1.0 (public research; contact via site)2

Country

fingerprintco-occurrences
CZ · Czechia541
FR · France21
US · United States13
NL · Netherlands13
CH · Switzerland5
DE · Germany3
BE · Belgium2
RU · Russia2
FI · Finland2
CA · Canada1

Network (ASN)

fingerprintco-occurrences
AS43037 · Seznam.cz, a.s.541
AS16276 · OVH SAS19
AS206238 · Freedom Internet BV13
AS7922 · Comcast Cable Communications, LLC10
AS29222 · Infomaniak Network SA5
AS24940 · Hetzner Online GmbH4
AS12322 · Free SAS2
AS6848 · Telenet BV2
AS51167 · Contabo GmbH1
AS16591 · Google Fiber Inc.1

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
q13d0315h3_55b375c5d22e_dc5437974b475
q13d0311h3_55b375c5d22e_653d80c3fe9d4
q13d0314h3_55b375c5d22e_61e396c58b1f2
q13d0315h3_55b375c5d22e_78345df32b3a2