Build a Secure DNS Resolver System

DNS is a critical internet protocol, but traditional queries are vulnerable to spoofing and interception. Attackers can redirect users to malicious websites by poisoning DNS caches or intercepting plaintext requests. A secure DNS resolver mitigates these threats and ensures query integrity and confidentiality.

This system acts as a local DNS resolver that routes queries securely using DNS-over-HTTPS (DoH) or DNS-over-TLS (DoT), and optionally verifies authenticity using DNSSEC. It includes logging, caching, and filtering to improve performance and enhance security posture.

The user’s device sends DNS queries to the custom resolver, which encrypts them using HTTPS or TLS before forwarding to a trusted upstream resolver like Cloudflare or Google. DNSSEC signatures are checked when available, and results are cached locally to improve performance and reduce redundant queries.

• Client sends a DNS request to your resolver.
• The resolver encrypts the query using DoH/DoT and forwards it upstream.
• Response is validated via DNSSEC (if enabled).
• Secure response is returned to the client and optionally cached.
• Suspicious domains are blocked based on blacklists or threat intel.

• CoreDNS Official Docs
• DNS-over-HTTPS Explained
• DNSCrypt Proxy
• Unbound DNSSEC Configuration
• dnspython Library