Implementing Zero Trust DNS with NextDNS

Overview

NextDNS is a cloud-based DNS resolver that provides encrypted DNS resolution (DNS-over-HTTPS and DNS-over-TLS), real-time threat intelligence blocking, ad and tracker filtering, and granular DNS policy enforcement. In a zero trust architecture, DNS is a critical control point -- every network connection begins with a DNS query, making DNS filtering an effective layer for blocking malicious domains, preventing data exfiltration via DNS tunneling, enforcing acceptable use policies, and gaining visibility into all network communications. NextDNS processes queries using threat intelligence feeds containing millions of malicious domains updated in real-time, blocks cryptojacking and phishing domains, detects DNS rebinding attacks, and supports CNAME cloaking protection. For enterprise environments, Microsoft's Zero Trust DNS (ZTDNS) feature on Windows 11 extends this concept by enforcing that endpoints can only resolve domains through approved protected DNS servers.

When to Use

• When deploying or configuring implementing zero trust dns with nextdns capabilities in your environment
• When establishing security controls aligned to compliance requirements
• When building or improving security architecture for this domain
• When conducting security assessments that require this implementation

Prerequisites

• NextDNS account (free tier: 300,000 queries/month; Pro: unlimited)
• Network devices supporting DoH or DoT configuration
• Administrative access to endpoint DNS settings
• Understanding of DNS protocol and resolution chain
• Familiarity with organizational acceptable use policies

Architecture

    Endpoint Device
         |
    DNS Query (Encrypted)
         |
    +----+----+
    |  DoH/DoT |  (DNS-over-HTTPS or DNS-over-TLS)
    |  Tunnel  |
    +----+----+
         |
    +----+----+
    | NextDNS  |
    | Resolver |
    +----+----+
         |
    +----+----+------+--------+
    |         |       |        |
  Threat   Ad/Tracker Privacy  Parental
  Intel    Blocklists Controls Controls
  Check    Check      Check    Check
    |         |       |        |
    +----+----+------+--------+
         |
    ALLOW or BLOCK
         |
    Response to Endpoint

Configuration Setup

NextDNS Profile Configuration

Dashboard: https://my.nextdns.io

Configuration ID: abc123 (unique per profile)

Endpoints:
  DNS-over-HTTPS: https://dns.nextdns.io/abc123
  DNS-over-TLS:   abc123.dns.nextdns.io
  DNS-over-QUIC:  quic://abc123.dns.nextdns.io
  IPv4:           45.90.28.x, 45.90.30.x (linked to config)
  IPv6:           2a07:a8c0::xx, 2a07:a8c1::xx

Security Settings

Security Tab Configuration:
  [x] Threat Intelligence Feeds - Block domains from curated threat feeds
  [x] AI-Driven Threat Detection - Machine learning-based detection
  [x] Google Safe Browsing - Cross-reference with Google's threat database
  [x] Cryptojacking Protection - Block crypto mining domains
  [x] DNS Rebinding Protection - Prevent DNS rebinding attacks
  [x] IDN Homograph Attacks - Block internationalized domain name attacks
  [x] Typosquatting Protection - Block common typosquatting domains
  [x] DGA Protection - Block domain generation algorithm domains
  [x] NRD (Newly Registered Domains) - Block domains < 30 days old
  [x] DDNS (Dynamic DNS) - Block dynamic DNS services
  [x] Parked Domains - Block parked/unused domains
  [x] CSAM - Block child sexual abuse material domains

Privacy Settings

Privacy Tab Configuration:
  Blocklists:
    [x] NextDNS Ads & Trackers Blocklist
    [x] OISD (Full)
    [x] EasyPrivacy
    [x] AdGuard DNS Filter

  Native Tracking Protection:
    [x] Block Windows telemetry
    [x] Block Apple telemetry
    [x] Block Samsung telemetry
    [x] Block Xiaomi telemetry
    [x] Block Huawei telemetry
    [x] Block Roku telemetry
    [x] Block Sonos telemetry

  [x] Block Disguised Third-Party Trackers (CNAME cloaking)
  [x] Allow Affiliate & Tracking Links (optional, for business)

Allowlist and Denylist

Allowlist (domains that bypass all blocking):
  - login.microsoftonline.com
  - graph.microsoft.com
  - *.company.com

Denylist (always blocked regardless of other settings):
  - known-malicious-domain.com
  - unauthorized-cloud-storage.com
  - personal-email-provider.com  (if policy requires)

Endpoint Deployment

Linux (systemd-resolved)

# Configure DNS-over-TLS with systemd-resolved

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