networking

DNS resolver

Also known as: resolver, recursive resolver

The DNS server a device asks for name-to-IP lookups. Whoever controls the resolver controls (and sees) everything.

A DNS resolver is the server an endpoint sends its DNS queries to. Out of the box, devices use whatever resolver DHCP hands them, usually the ISP’s. An MSP-managed environment changes this so queries flow through a protective resolver that can log, filter, and block.

Resolvers can be set:

  • At the router/firewall (DHCP option 6), easiest, applies to every device on the LAN
  • Per device via local DNS settings or a roaming client agent (DNSFilter Roaming Client, Cloudflare WARP, etc.)
  • Per profile in mobile MDM
  • Via Encrypted DNS (DoH/DoT), same idea, but the queries can’t be intercepted on the path

The roaming-client option matters because it keeps protection on when users leave the office network.