DNS

Also known as: Domain Name System

Domain Name System, the internet's phonebook. Translates human-readable names like "example.com" into IP addresses computers actually connect to.

DNS turns names into numbers. When a user opens example.com, the operating system asks a DNS resolver “what IP do I send packets to?” The resolver walks the DNS hierarchy (root → TLD → authoritative nameserver) and returns an answer. The browser then connects to that IP.

Why an MSP cares: every web request, every cloud login, every Microsoft 365 sync starts with a DNS lookup. Owning the DNS resolver path means you can:

Block malicious domains before any TCP connection happens (the basis of DNS filtering)
Filter inappropriate content by category
See what’s actually being accessed across an entire fleet without installing endpoint agents
Speed up resolution with anycast resolvers near the user

Common managed-DNS-resolver products in the MSP world: DNSFilter, Cisco Umbrella, Cloudflare Gateway, Webroot DNS Protection.