DevNS

DevNS is a lightweight local DNS server for development purposes, it listens on UDP port 53 (configurable) and answers DNS queries by resolving them via Node's built-in dns module, with support for local hosts file overrides.

DevNS is developed by AI. Also a Tinkink project.

Features

• Lightweight & Fast: Minimal dependencies, built on Node.js built-in modules
• UDP DNS Server: Listens for DNS queries on configurable UDP port
• Hosts File Support: Reads and watches system hosts file for local overrides
• Multiple Record Types: Supports A, AAAA, CNAME, MX, NS, PTR, SRV, TXT, and ANY queries
• Standard Logging: Clean console output with clear server status messages
• Error Handling: Graceful error handling with automatic retry mechanisms
• Production Ready: Suitable for both development and production environments

Installation

Global Installation (Recommended)

npm install -g devns

Local Installation

npm install devns

From Source

git clone <repository-url>
cd dns-server
npm install
npm run build

Usage

Command Line Options

devns [options]

Options:
  -p, --port <port>   UDP port to listen on (default: 53)
  -H, --host <host>   Host/IP to bind (default: 0.0.0.0)
  --ttl <seconds>     TTL for synthesized answers (default: 300)
  -h, --help          Show help

Examples

Development (Non-privileged port)

# Start server on port 1053 (no sudo required)
npx devns --port 1053

# Or if installed globally
devns --port 1053

Test with dig:

dig @127.0.0.1 -p 1053 example.com A
dig @127.0.0.1 -p 1053 google.com AAAA

Production (Port 53 requires elevated privileges)

# Start server on standard DNS port (requires sudo)
sudo devns --host 0.0.0.0 --port 53

Custom Host and TTL

devns --host 127.0.0.1 --port 5353 --ttl 600

Development Mode

If you're working on the source code:

# Install dependencies
npm install

# Run in development mode (auto-reload on changes)
npm run dev -- --port 1053

# Build for production
npm run build

# Run built version
npm start -- --port 1053

Supported DNS Record Types

The server supports the following DNS query types:

• A: IPv4 address records
• AAAA: IPv6 address records
• CNAME: Canonical name records
• MX: Mail exchange records
• NS: Name server records
• PTR: Pointer records (reverse DNS)
• SRV: Service records
• TXT: Text records
• ANY: Returns all available record types

Hosts File Support

The server automatically reads and watches your system's hosts file:

• Linux/macOS: /etc/hosts
• Windows: C:/Windows/System32/drivers/etc/hosts

Any entries in the hosts file will override external DNS resolution. The server watches for changes and reloads the hosts file automatically.

Technical Details

• Protocol: UDP (TCP not supported)
• Maximum Response Size: 512 bytes (no EDNS support)
• Recursive Resolver: Sets RA flag and copies RD from requests
• Error Handling: Returns appropriate DNS response codes (NXDOMAIN, SERVFAIL, etc.)
• Logging: Clean console output with server status and query information

Requirements

• Node.js 16.0.0 or higher
• UDP port access (port 53 for standard DNS, or any available port for development)

Security Notes

• Running on port 53 requires elevated privileges (sudo/admin access)
• The server only responds to UDP DNS queries and doesn't support TCP
• Hosts file entries take precedence over external DNS resolution
• No authentication or access control - ensure proper firewall configuration

License

MIT

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.