The 3 types of DNS servers and how they work
DNS root server | Cloudflare
DNS servers: what they are and how they work - G-Core Labs' blog
DNSサーバーと種類 | Cloudflare
networking - Who controls the DNS servers? - Super User
network manager - What is my DNS server? - Ask Ubuntu
Introducing Important Types of DNS Servers (Powerful)
Novell Documentation
What are the root DNS servers, and where are they located? - Quora
What is a DNS Server and how does it work? - Seobility Wiki
The ultimate guide to changing your DNS server
Configure DNS Server Zones Fully on Windows Server 2016? – Tactig
DNSサーバーと種類 | Cloudflare
What is Secondary DNS? Different DNS configurations.
DNSサーバーと種類 | Cloudflare
What are root name servers? | Netnod
DNS Server - Network Encyclopedia
101: What is DNS -- and why is it important?
Primary DNS vs. Secondary DNS and Advanced Use Cases
What is The Usage of DNS
Networking Basics: Part 3 - DNS Servers
AskF5 | Manual Chapter: Replacing a DNS Server with BIG-IP DNS
