TCP SYN (p0f)

4:241+14:0:1420:mss*42,8:mss,nop,ws,sok,eol+1:df,id+:0

first seen 2026-06-26 11:53 · last seen 2026-10-19 08:17 · 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

IP version4
Initial TTL241+14
Options length0
MSS1420
Window sizemss*42
Window scale8
Options layoutmss,nop,ws,sok,eol+1
Quirksdf,id+
Payload class0

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
t13d0916h2_f91f431d341e_0c27189014cf24
t13d0917h2_f91f431d341e_3cbfd9057e0d14

HTTP request (JA4H)

fingerprintco-occurrences
ge20nr13enus_016d87568c43_000000000000_00000000000023
ge20nr12enus_979a40433f82_000000000000_00000000000010
ge20nr14enus_eb31b0d20d08_000000000000_0000000000002
ge20nr13enus_477eefb733f8_000000000000_0000000000002
ge20nr14enus_d2a148ad830b_000000000000_0000000000001

HTTP/2 frames (Akamai)

fingerprintco-occurrences
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.9
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, +31 more.The fingerprint page shows the full measured match list. More on the catalog.8
1:65536;2:0;4:131072;5:16384|12517377|9:0:0:42|m,p,a,s2
1:65536;2:0;4:131072;5:16384|12517377|5:0:0:22|m,p,a,s Match?Exact match in Thumbprint's published controlled catalog captures: firefox 153.0.3, firefox 154.0, firefox 153.0, +12 more.The fingerprint page shows the full measured match list. More on the catalog.2
1:65536;2:0;4:131072;5:16384|12517377|7:0:0:22|m,p,a,s Match?Exact match in Thumbprint's published controlled catalog captures: firefox 153.0.3, firefox 155.0, firefox 154.0, +3 more.The fingerprint page shows the full measured match list. More on the catalog.2
1:65536;2:0;4:131072;5:16384|12517377|11:0:0:42|m,p,a,s2
1:65536;2:0;4:131072;5:16384|12517377|5:0:0:42|m,p,a,s2
1:65536;2:0;4:131072;5:16384|12517377|17:0:0:42|m,p,a,s1
1:65536;2:0;4:131072;5:16384|12517377|13:0:0:42|m,p,a,s1
1:65536;2:0;4:131072;5:16384|12517377|15:0:0:42|m,p,a,s1

TCP SYN (JA4T)

fingerprintco-occurrences
59640_2-1-3-4-0-0_1420_834

User-Agent

fingerprintco-occurrences
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:152.0) Gecko/20100101 Firefox/152.034
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:158.0) Gecko/20100101 Firefox/158.03
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:155.0) Gecko/20100101 Firefox/155.01

Country

fingerprintco-occurrences
FR · France38

Network (ASN)

fingerprintco-occurrences
AS15557 · Societe Francaise Du Radiotelephone - SFR SA38

TLS supported groups

fingerprintco-occurrences
11ec,001d,0017,0018,0019 Match?Exact match in Thumbprint's published controlled catalog captures: firefox 157.0.1, firefox-esr 153.5.1esr, firefox 158.0.1, +3 more.The fingerprint page shows the full measured match list. More on the catalog.3

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