TCP SYN (JA4T)

43200_2-4-8-1-3_1440_10

first seen 2026-07-01 14:45 · last seen 2026-10-30 17:47 · JSON

Last 7 days (1 observations)

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 window43200
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
t13d1712h1_ab0a1bf427ad_882d495ac3818
t13d190900_9dc949149365_97f8aa674fd95
t13d2013h2_a09f3c656075_7f0f34a4126d Match?Exact match in Thumbprint's published controlled catalog captures: safari 26.5.2, safari 26.6.2, safari 26.4, +2 more.The fingerprint page shows the full measured match list. More on the catalog.3
t13d3112h2_e8f1e7e78f70_b26ce05bbdd6 Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.5.0, php-curl 7.88.1.The fingerprint page shows the full measured match list. More on the catalog.2
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.2
t13d491100_834380eab35e_d41ae481755e2
t13d1716h2_5b57614c22b0_ca3c9f3127702
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.1
t13d4312h1_c7886603b240_b26ce05bbdd61
t13d191000_9dc949149365_e7c2852226511

HTTP request (JA4H)

fingerprintco-occurrences
ge11nn050000_b223a0ebb0b5_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: python-requests 2.34.2, python-requests 2.33.1, python-requests 2.32.3.The fingerprint page shows the full measured match list. More on the catalog.9
ge11nn040000_e1d2031bdfea_000000000000_0000000000005
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_0000000000002
ge11nn050000_212a08913770_000000000000_0000000000002
ge20nr09zhcn_538441e4e116_000000000000_0000000000002
ge11nr040000_8391bea91fb6_000000000000_0000000000001
ge20nr10enus_b3034183f430_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: firefox 153.0, firefox 153.0.3, firefox 155.0.1, +28 more.The fingerprint page shows the full measured match list. More on the catalog.1
ge20nn11enus_3901d4197baf_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: firefox 154.0, firefox 152.0.5, firefox 153.0.1, +3 more.The fingerprint page shows the full measured match list. More on the catalog.1
ge20nr09enus_d05bf764aa1e_000000000000_0000000000001

HTTP/2 frames (Akamai)

fingerprintco-occurrences
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 26.6.2, safari 26.5, +3 more.The fingerprint page shows the full measured match list. More on the catalog.3
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.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.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.1
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 152.0.7977.83, +85 more.The fingerprint page shows the full measured match list. More on the catalog.1
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)

fingerprintco-occurrences
6:55+9:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:07
6:56+8:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:05
6:52+12:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:03
6:51+13:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:03
6:61+3:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:03
6:53+11:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:02
6:49+15:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:01
6:48+16:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:01
6:45+19:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:01
6:50+14:0:1440:mss*30,10:mss,sok,ts,nop,ws:flow:01

User-Agent

fingerprintco-occurrences
Mozilla/5.0 (compatible; SecurityScanner/1.0)6
Mozilla/5.0 (compatible; CensysInspect/1.1; +https://about.censys.io/)5
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/27.0 Safari/605.1.153
wget/http3check.net2
curl/8.14.12
curl/8.5.02
Mozilla/5.0 (compatible; SecurityScanner/1.0; +https://tokenfaucet.fun)2
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:154.0) Gecko/20100101 Firefox/154.02
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.361
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.361

Country

fingerprintco-occurrences
US · United States10
SG · Singapore10
HK · Hong Kong SAR China5
GB · United Kingdom1
MX · Mexico1

Network (ASN)

fingerprintco-occurrences
AS20473 · The Constant Company, LLC16
AS398722 · Censys, Inc.5
AS63150 · BAGE CLOUD LLC3
AS219329 · FLASH EDGE INFORMATION TECHNOLOGY LLC2
AS204044 · Packet Star Networks Limited1

TLS supported groups

fingerprintco-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
001d,0017,001e,0019,0018,0100,0101,0102,0103,0104 Match?Exact match in Thumbprint's published controlled catalog captures: curl 8.13.0, php-guzzle 8.3.1, curl 7.88.1, +10 more.The fingerprint page shows the full measured match list. More on the catalog.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
q13d0311h3_55b375c5d22e_653d80c3fe9d1