Securing Your Local Network with DNS over HTTPS (DoH): A Comprehensive Guide

DNS over HTTPS (DoH) is rapidly gaining popularity as a method to enhance the privacy and security of your internet browsing. While often discussed in the context of your internet service provider (ISP), setting up DoH locally offers even greater control and benefits, particularly for families or those managing a small network.

What is Local DNS over HTTPS?

Local DoH involves running a DNS resolver on your local network (e.g., a Raspberry Pi, a dedicated server, or even a powerful desktop PC) that handles DNS queries over HTTPS. This means that all DNS requests from devices on your network are encrypted and sent to your chosen DoH provider, preventing your ISP or potential eavesdroppers from seeing which websites you're visiting.

Benefits of Using Local DoH

• Enhanced Privacy: Your DNS queries are encrypted, preventing your ISP and others from tracking your browsing activity.
• Improved Security: DoH protects against DNS spoofing and other attacks that could redirect you to malicious websites.
• Network-Wide Protection: All devices on your network benefit from the enhanced security and privacy, not just a single computer.
• Control and Customization: You have complete control over the DNS resolver and can choose a provider that aligns with your privacy preferences.
• Bypass Censorship (In some cases): A locally hosted DoH server can potentially help bypass certain forms of internet censorship.

Choosing a DoH Provider

Several reputable DoH providers are available, each with its own strengths and weaknesses. Popular choices include:

• Cloudflare (1.1.1.1): Known for its speed and privacy focus.
• Google Public DNS (8.8.8.8): A widely used and reliable option.
• Quad9 (9.9.9.9): Emphasizes security and blocking malicious domains.
• NextDNS: Offers advanced features and customization options (often requires a paid subscription).

Consider factors such as speed, privacy policy, and blocking capabilities when selecting a provider.

Setting up a Local DoH Server (Example using unbound and Caddy)

This example uses unbound as the DNS resolver and Caddy as the HTTPS server. This combination offers a robust and secure solution.

1. Installation

Install unbound and Caddy on your chosen server. The exact commands will depend on your operating system (e.g., apt-get install unbound caddy on Debian/Ubuntu).

2. Unbound Configuration

Configure unbound to use your chosen DoH provider. A sample unbound.conf file might look like this:

forward-zone:
    name: "0.0.0.0"
    forward-addr: 1.1.1.1@853 # Cloudflare DoH
    forward-addr: 8.8.8.8@853 # Google DoH (optional)
    forward-tls-upstream: yes

interface:
    listen-on: 127.0.0.1
    listen-on: ::1
    port: 53
    tls-port: 853

Remember to adjust the forward-addr to match your chosen DoH provider and port (usually 853).

3. Caddy Configuration

Configure Caddy to act as a reverse proxy, forwarding requests to unbound over HTTPS. A sample Caddyfile might look like this:

localhost:53 {
  redir https://localhost:853
}

localhost:853 {
  tls
  handle "dns-over-https" {
      dns unbound { 
          address localhost:53
          upstream localhost:53
      }
  }
}

4. Client Configuration

Finally, configure your devices to use your local DoH server. This usually involves setting the DNS server address to your server's IP address and port 853 in your network settings.

Troubleshooting and Security Considerations

Ensure your server is properly secured with strong passwords and firewalls. Regularly update unbound and Caddy to patch security vulnerabilities. Monitor your server's logs for any suspicious activity.

Implementing local DoH significantly improves the privacy and security of your local network. While setting it up requires some technical knowledge, the benefits far outweigh the effort involved for those who value online privacy.