Securing Your Ubuntu 24.04 Network: A Comprehensive Guide to DNS over HTTPS (DoH)

DNS over HTTPS (DoH) enhances your online privacy and security by encrypting your DNS queries. This guide will walk you through configuring DoH on your Ubuntu 24.04 system, exploring various methods and addressing potential issues.

Why Use DNS over HTTPS?

Traditional DNS queries are sent in plain text, making them vulnerable to eavesdropping and manipulation. DoH solves this by encrypting these queries over HTTPS, providing several key benefits:

Increased Privacy: Your ISP and other network observers cannot see which websites you're accessing.
Improved Security: Protects against DNS spoofing and cache poisoning attacks.
Resistance to Censorship: Makes it harder for entities to block access to specific websites.

Methods for Configuring DoH on Ubuntu 24.04

Several methods exist for enabling DoH on Ubuntu 24.04. We'll explore the most common and reliable approaches.

Method 1: Using NetworkManager (Recommended for most users)

Using NetworkManager

NetworkManager provides a user-friendly interface for managing network connections. This method is generally recommended for its ease of use.

Open Network Settings: Click on the network icon in the top right corner of your screen and select "Settings."
Select your connection: Choose the Wi-Fi or Ethernet connection you wish to configure.
IPv6 Settings (Optional): If you're using IPv6, ensure it's enabled.
DNS settings: Look for a DNS settings section. Most NetworkManager implementations now offer a direct DoH setting. If not, you may need to manually enter a DoH address like:

https://dns.google/dns-query

Apply changes: Click "Apply" or "Save" to apply your settings.
Verify: Run systemd-resolve --status in your terminal to check if the changes have been applied.

Method 2: Modifying `/etc/systemd/resolved.conf`

Modifying `/etc/systemd/resolved.conf`

This method offers more control but requires root privileges. It's generally preferred for server setups or users who require more granular configuration.

Open the file: Use a text editor with root privileges (e.g., sudo nano /etc/systemd/resolved.conf).
Add the DoH line: Add the following line, replacing `https://dns.google/dns-query` with your preferred DoH server address:

DNS=https://dns.google/dns-query

Save and restart: Save the file and restart the `systemd-resolved` service using sudo systemctl restart systemd-resolved.
Verify: Use systemd-resolve --status to confirm the changes.

Method 3: Using a DoH-capable DNS client (e.g., unbound)

Using unbound

Using a dedicated DNS client like unbound provides advanced features and customization options. However, it's a more complex setup.

This method involves installing and configuring unbound, then configuring your system to use it as the primary DNS resolver. Detailed instructions for this method would be extensive and are best covered in a separate guide.

Choosing a DoH Provider

Several reputable providers offer DoH services. Popular choices include:

Google Public DNS over HTTPS: `https://dns.google/dns-query`
Cloudflare DNS over HTTPS: `https://cloudflare-dns.com/dns-query`
Quad9 DNS over HTTPS: `https://dns.quad9.net/dns-query`

Consider the privacy policies and security practices of each provider before making a selection.

Troubleshooting

If you encounter issues after configuring DoH, check the following:

Verify your configuration: Ensure you've correctly entered the DoH address and restarted the relevant services.
Check network connectivity: Ensure your internet connection is stable.
Firewall rules: Ensure your firewall isn't blocking DoH traffic on port 443.
DNS server status: Check if your chosen DoH provider is experiencing any outages.

By following these steps, you can effectively secure your Ubuntu 24.04 network using DNS over HTTPS and enjoy the benefits of enhanced privacy and security.