TCP SYN (JA4T)

21900_2-4-8-1-3_1460_10

first seen 2026-07-15 10:07 · last seen 2026-09-09 06:28 · JSON

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 window21900
Option kinds2-4-8-1-3
MSS1460
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
t13d190900_9dc949149365_97f8aa674fd97

HTTP request (JA4H)

fingerprintco-occurrences
ge11nn040000_e1d2031bdfea_000000000000_0000000000007

TCP SYN (p0f)

fingerprintco-occurrences
4:52+12:0:1460:mss*15,10:mss,sok,ts,nop,ws:df,id+:04
4:56+8:0:1460:mss*15,10:mss,sok,ts,nop,ws:df,id+:03

User-Agent

fingerprintco-occurrences
Mozilla/5.0 (compatible; CensysInspect/1.1; +https://about.censys.io/)7

Country

fingerprintco-occurrences
US · United States4
DE · Germany3

Network (ASN)

fingerprintco-occurrences
AS398324 · Censys, Inc.4
AS398705 · Censys, Inc.3