PrismDNS is a lightweight, high-performance authoritative DNS proxy written in Go. It acts as a DNS server that routes queries to different upstream DNS servers based on the domain being queried. This allows multiple DNS servers to share the same public IP address.

• Domain-based routing: Forward DNS queries to different upstream servers based on domain names
• Fallback routing: Configurable fallback server when no specific route matches
• Health checks: Automatic health monitoring of upstream servers every 5 seconds
• Rate limiting: Built-in rate limiting to prevent abuse (configurable per domain or globally)
• HTTP API: RESTful API for dynamic route management without restarting the server

Start PrismDNS with your routes:

./PrismDNS-linux-amd64 \
  -route example.com,10.0.1.5 \
  -route dept.example.com,10.0.2.8 \
  -route api.internal,10.0.1.6 \
  -fallback 10.0.1.7:1053 \
  -http-api-key your-secret-api-key

For a full list of flags, run ./PrismDNS-linux-amd64 -help

docker run -d \
  -p 53:53/udp \
  -p 53:53/tcp \
  -p 8053:8053 \
  truewinter/prismdns:{version} \
  -route example.com,10.0.1.5 \
  -route dept.example.com,10.0.2.8 \
  -route api.internal,10.0.1.6 \
  -fallback 10.0.1.7:1053 \
  -http-api-key your-secret-api-key

Images are not published with the latest tag. Check the releases page for the latest version.

For a full list of flags, run docker run prismdns -help

All API requests require the X-Api-Key header (except for the apex /healthcheck and /metrics endpoints).

List all configured routes.

Response:

[
  {"Domain":"example.com","Ip":"10.0.1.5","Port":53},
  {"Domain":"api.internal","Ip":"10.0.2.8","Port":53}
]

Add a new route.

Request:

{"Domain":"newdomain.com","Ip":"10.0.3.5","Port":53}

Modify an existing route.

Request:

{"Ip":"example.com","Port":5300}

Delete a route.

Get health status of all configured routes.

Response:

[
  {
    "Domain":"example.com",
    "Ip": "10.0.1.5",
    "Port": 53,
    "Health": {
      "Ok": true,
      "Error": "",
      "LastCheck": 1779670849,
      "LastCheckLatency": 1.204
    }
  }
]

Basic health check endpoint for the HTTP API (no authentication required).

Get health status of a specific route. See GET /healthcheck/routes.

Prometheus metrics endpoint (no authentication required). A pre-built Grafana dashboard is available for your convenience.

For troubleshooting, PrismDNS supports DNS CHAOS queries for version information:

# Returns the version
dig @10.0.53.53 CH TXT version.bind

# Returns the server ID set by the server-id flag
dig @10.0.53.53 CH TXT id.server

Build the binaries for your platform:

./build.sh

This compiles both Linux and Windows executables to the dist/ directory.

docker build -t truewinter/prismdns .