Securing Your Ubuntu 22.04 Network: A Comprehensive Guide to DNS over HTTPS

DNS over HTTPS (DoH) enhances your online privacy and security by encrypting your DNS queries. This means your internet service provider (ISP) and other potential eavesdroppers can no longer see which websites you're visiting. This guide provides a detailed walkthrough of configuring DoH on your Ubuntu 22.04 system, covering various methods and troubleshooting steps.

Why Use DNS over HTTPS on Ubuntu 22.04?

Traditional DNS uses unencrypted queries, making your browsing history vulnerable. DoH addresses this by tunneling DNS lookups through HTTPS, providing several key benefits:

• Enhanced Privacy: Prevents your ISP and others from monitoring your browsing activity.
• Improved Security: Protects against DNS spoofing and other attacks that manipulate DNS responses.
• Censorship Resistance: Can help bypass censorship efforts that manipulate DNS records.

Methods for Configuring DNS over HTTPS on Ubuntu 22.04

There are several ways to implement DoH on Ubuntu 22.04. We'll explore the most common and effective approaches:

1. Using NetworkManager (Recommended for most users)

NetworkManager is a powerful tool for managing network connections. Most desktop users will find this the easiest method. This involves modifying your network connection settings to specify a DoH-enabled DNS resolver.

1. Open NetworkManager settings (search for "Network" in your applications menu).
2. Select your currently active network connection (e.g., Wi-Fi or Ethernet).
3. Click the "IPv4" or "IPv6" tab (depending on your connection type).
4. In the "DNS" section, you'll typically find an option for "Method." Choose "Automatic (DHCP) addresses only" if not already selected.
5. Add the desired DoH provider's address in the "DNS servers" section. For example, for Cloudflare, use 1.1.1.1. You can add multiple servers, separating them with spaces. Note: Using this method alone does not guarantee DoH. Many providers require additional settings in the next steps.
6. Some NetworkManager versions offer a dedicated “DNS over HTTPS” setting. If available, enable it and select your preferred provider.
7. Save your changes. You might need to disconnect and reconnect to your network for the changes to take effect.

Important Considerations for NetworkManager: While NetworkManager *can* support DoH, its implementation varies slightly among distributions and versions. You may need to consult your specific NetworkManager documentation for advanced configurations.

2. Modifying the systemd-resolved Configuration File

This method offers more granular control but requires editing a configuration file. It's suitable for users comfortable with command-line tools.

1. Open the systemd-resolved configuration file using a text editor with root privileges:

sudo nano /etc/systemd/resolved.conf

2. Add or modify the following lines, replacing with your preferred provider's address. Examples:
   • Cloudflare: dns=cloudflare-dns.com
   • Google Public DNS: dns=dns.google
   • Quad9: dns=dns.quad9.net
3. Save and close the file.
4. Restart systemd-resolved:

sudo systemctl restart systemd-resolved

3. Using a Custom DNS Client (Advanced Users)

For users needing advanced features or fine-grained control, using a dedicated DoH client like `doh-client` provides enhanced flexibility but requires more technical expertise.

Verifying DoH is Working

After configuring DoH, you can verify its functionality using online tools or command-line utilities. These tools analyze your DNS queries to confirm encryption. Search online for “DNS leak test” to find suitable websites.

Troubleshooting

If DoH isn't working, try the following:

• Check your network connection: Ensure you're connected to the internet.
• Verify your configuration: Double-check the DoH provider address and other settings.
• Restart your network services: Restart NetworkManager or systemd-resolved.
• Reboot your system: A system reboot can sometimes resolve connectivity issues.

This comprehensive guide helps you secure your Ubuntu 22.04 system with DNS over HTTPS. Remember to choose a reputable DoH provider and always keep your system updated for optimal security.