TCP SYN (JA4T)

65535_2-1-3-1-1-8-4-0-0_1390_6

first seen 2026-07-05 13:26 · last seen 2026-09-06 00:03 · 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

TCP window65535
Option kinds2-1-3-1-1-8-4-0-0
MSS1390
Window scale6

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
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
t13d2013h2_a09f3c656075_7f0f34a4126d Match?Exact match in Thumbprint's published controlled catalog captures: safari 26.5.2, safari 26.4, safari 26.6.2, +2 more.The fingerprint page shows the full measured match list. More on the catalog.6
t13d4907h2_0d8feac7bc37_7395dae3b2f3 Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.7.1.The fingerprint page shows the full measured match list. More on the catalog.2
t13d3112h1_e8f1e7e78f70_8d633dac71242

HTTP request (JA4H)

fingerprintco-occurrences
ge20nr12dede_54b4638ab28b_000000000000_0000000000008
ge20nr09enus_538441e4e116_000000000000_0000000000006
ge11nn030000_fe444ad14866_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.16.0.The fingerprint page shows the full measured match list. More on the catalog.2
he20nn020000_5594a17e7e7e_000000000000_0000000000001
ge20nn020000_5594a17e7e7e_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.7.1, curl 8.5.0, curl 8.18.0, +9 more.The fingerprint page shows the full measured match list. More on the catalog.1

HTTP/2 frames (Akamai)

fingerprintco-occurrences
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.7
2:0;3:100;4:2097152;9:1|10420225|0|m,s,a,p Match?Exact match in Thumbprint's published controlled catalog captures: safari 26.5.2, safari 26.5, safari 26.4, +2 more.The fingerprint page shows the full measured match list. More on the catalog.6
3:100;4:10485760;2:0|1048510465|0|m,s,a,p Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.7.1, curl 8.5.0.The fingerprint page shows the full measured match list. More on the catalog.2
1:65536;2:0;4:6291456;6:262144|15663105|3:1:1:220|m,a,s,p Match?Exact match in Thumbprint's published controlled catalog captures: chrome 150.0.7871.128, chrome 150.0.7871.115, chrome 151.0.7922.174, +7 more.The fingerprint page shows the full measured match list. More on the catalog.1

TCP SYN (p0f)

fingerprintco-occurrences
6:43+21:0:1390:65535,6:mss,nop,ws,nop,nop,ts,sok,eol+1:ecn,flow:06
6:238+17:0:1390:65535,6:mss,nop,ws,nop,nop,ts,sok,eol+1:ecn,flow:02
6:41+23:0:1390:65535,6:mss,nop,ws,nop,nop,ts,sok,eol+1:ecn,flow:02
6:40+24:0:1390:65535,6:mss,nop,ws,nop,nop,ts,sok,eol+1:ecn,flow:02
6:42+22:0:1390:65535,6:mss,nop,ws,nop,nop,ts,sok,eol+1:ecn,flow:02
6:45+19:0:1390:65535,6:mss,nop,ws,nop,nop,ts,sok,eol+1:flow:02
6:39+25:0:1390:65535,6:mss,nop,ws,nop,nop,ts,sok,eol+1:ecn,flow:01
6:43+21:0:1390:65535,6:mss,nop,ws,nop,nop,ts,sok,eol+1:ecn:01

User-Agent

fingerprintco-occurrences
Mozilla/5.0 (iPhone; CPU iPhone OS 18_7 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.5 Mobile/15E148 Safari/604.16
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/151.0.0.0 Safari/537.365
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.363
curl/8.7.12
curl/8.1.22

Country

fingerprintco-occurrences
DE · Germany8
EE · Estonia6
SG · Singapore2
TW · Taiwan2

Network (ASN)

fingerprintco-occurrences
AS6805 · Telefonica Germany GmbH & Co.OHG8
AS1257 · Tele2 Sverige AB6
AS45143 · SINGTEL MOBILE INTERNET SERVICE PROVIDER Singapore2
AS9674 · Far EastTone Telecommunication Co., Ltd.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).

fingerprintlinked observations
q13d0311h3_55b375c5d22e_653d80c3fe9d7
q13d0311h3_55b375c5d22e_f2a83c8e78ae2