TCP SYN (JA4T)

65535_2-4-8-1-3_1380_13

first seen 2026-07-01 03:37 · last seen 2026-09-02 09:37 · JSON

Distinct clients per day (last 30 days, peak 4/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
MSS1380
Window scale13

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_d8a2da3f94cd Match?Exact match in Thumbprint's published controlled catalog captures: chromium 149.0.7827.102, chrome 149.0.7827.102, chrome 149.0.7827.156, +25 more.The fingerprint page shows the full measured match list. More on the catalog.70
t13d1011h1_61a7ad8aa9b6_3a8073edd8ef56
t13d180900_796efca44d18_1497af28dee97
t13d1511h2_8daaf6152771_78e6aca7449b3
t13d1516h2_8daaf6152771_cd486ad61c781
t13d1517h2_8daaf6152771_68c5a8c2958d1
t13d1616h2_86a278354501_ca3c9f3127701
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.1
t13d1617h2_86a278354501_3cbfd9057e0d Match?Exact match in Thumbprint's published controlled catalog captures: firefox 153.0, firefox 153.0.3, firefox 152.0.3, +10 more.The fingerprint page shows the full measured match list. More on the catalog.1
t13d1312h2_f57a46bbacb6_ab7e3b40a677 Match?Exact match in Thumbprint's published controlled catalog captures: go-net/http 1.26.6, go-net/http 1.26.8, go-net/http 1.26.7, +5 more.The fingerprint page shows the full measured match list. More on the catalog.1

HTTP request (JA4H)

fingerprintco-occurrences
ge20nn020000_fb4f949fd323_000000000000_00000000000015
ge11nr04enus_3adac55f58e9_000000000000_00000000000011
he11nr04enus_3adac55f58e9_000000000000_0000000000007
ge11nn16enus_0d6ca22ab264_000000000000_0000000000006
ge11nr11enus_1fab05156ead_000000000000_0000000000005
he11nr13enus_ed40770a2e50_000000000000_0000000000005
ge11nr05enus_3bd45b6f184e_000000000000_0000000000004
he11nr05enus_3bd45b6f184e_000000000000_0000000000004
ge11nr13enus_ed40770a2e50_000000000000_0000000000004
he11nr06enus_85f58504866d_000000000000_0000000000004

HTTP/2 frames (Akamai)

fingerprintco-occurrences
2:0;4:4194304;5:16384;6:262144;1:65536|1073741824|0|a,m,p,s47
2:0;4:4194304;5:16384;6:10485760|1073741824|0|a,m,p,s Match?Exact match in Thumbprint's published controlled catalog captures: go-net/http 1.26.6, go-net/http 1.26.8, go-net/http 1.26.7, +6 more.The fingerprint page shows the full measured match list. More on the catalog.22
2:0;4:2097152;5:16384;6:16777216|5177345|0|m,s,a,p3
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.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;4:131072;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.2
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.1

TCP SYN (p0f)

fingerprintco-occurrences
4:51+13:0:1380:65535,13:mss,sok,ts,nop,ws:df,id+:074
4:53+11:0:1380:65535,13:mss,sok,ts,nop,ws:df,id+:042
4:55+9:0:1380:65535,13:mss,sok,ts,nop,ws:df,id+:020
4:54+10:0:1380:65535,13:mss,sok,ts,nop,ws:df,id+:04
4:52+12:0:1380:65535,13:mss,sok,ts,nop,ws:df,id+:02
4:47+17:0:1380:65535,13:mss,sok,ts,nop,ws:df,id+:02
4:56+8:0:1380:65535,13:mss,sok,ts,nop,ws:df,id+:01

User-Agent

fingerprintco-occurrences
Mozilla/5.0 (compatible; Applebot/0.1; +http://www.apple.com/go/applebot)37
Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)11
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.3611
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.369
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.368
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ChatGPT-User/1.0; +https://openai.com/bot)8
Mozilla/5.0 (Macintosh; Intel Mac OS X 14_5) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.4 Safari/605.1.158
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.367
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.07
Mozilla/5.0 (Linux; Android 14; Pixel 8) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.6422.113 Mobile Safari/537.366

Country

fingerprintco-occurrences
FR · France49
US · United States44
NL · Netherlands22
SG · Singapore18
BR · Brazil3
DE · Germany2
RU · Russia2
PL · Poland2
SE · Sweden1
IN · India1

Network (ASN)

fingerprintco-occurrences
AS13335 · Cloudflare, Inc.145

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_dc5437974b472