Securing Your Fedora Linux System: A Comprehensive Guide to DNS over HTTPS (DoH)

DNS over HTTPS (DoH) is a privacy-enhancing technique that encrypts your DNS queries, preventing your internet service provider (ISP) and other potential eavesdroppers from seeing which websites you visit. This guide provides a comprehensive walkthrough of setting up and configuring DoH on your Fedora Linux system, exploring various methods and addressing common issues.

Why Use DNS over HTTPS on Fedora?

Traditional DNS queries are sent in plain text, making them vulnerable to interception and manipulation. DoH addresses this by encrypting your DNS requests using HTTPS, the same protocol used for secure web browsing. This offers several key benefits:

• Enhanced Privacy: Your ISP and others cannot see your browsing activity.
• Improved Security: Protects against DNS spoofing and other attacks that target unencrypted DNS queries.
• Faster Resolution (Potentially): Some DoH providers offer faster DNS resolution than traditional DNS servers.

Methods for Enabling DoH on Fedora

Fedora offers several ways to enable DoH, ranging from simple configuration changes to using dedicated applications. Let's explore some of the most popular options:

1. Systemd-resolved (Recommended):

systemd-resolved is Fedora's default DNS resolver. It's highly configurable and integrates seamlessly with the system. To enable DoH, modify the /etc/systemd/resolved.conf file. Add or uncomment the following lines, replacing with your preferred DoH server address (e.g., cloudflare-dns.com, dns.google, doh.opendns.com):

[Resolve] 
DNS=8.8.8.8, 8.8.4.4  # Optional: Keep existing DNS servers if you need them
DNSOverHTTPS=yes
DNSOverHTTPSUsePeering=no
Domains=~none #Optional: to override default domains
DNSOverHTTPSPort=443
DNSOverHTTPSFallback=no

Save the file, then restart systemd-resolved:

sudo systemctl restart systemd-resolved

Verify the configuration using:

sudo systemd-resolve --status

2. NetworkManager:

If you manage your network connections through NetworkManager, you can configure DoH directly in the graphical interface. The exact steps vary depending on your version of NetworkManager, but generally involve editing the connection settings for your network and specifying the DoH server under the IPv4 or IPv6 settings.

3. Using a Different DNS Client:

Some DNS clients, like NetworkManager, offer built-in support for DoH. Check the documentation of your chosen client to see if it offers DoH configuration options.

Choosing a DoH Provider:

Several reputable providers offer DoH services. Consider the following factors when selecting a provider:

• Privacy Policy: Review the provider's privacy policy to understand how they handle your data.
• Performance: Test the performance of different providers to find one that offers fast and reliable resolution.
• Security: Choose a provider with a strong security track record.

Troubleshooting:

If you encounter issues, check the following:

• Firewall: Ensure your firewall isn't blocking port 443 (HTTPS).
• Configuration Errors: Double-check your resolved.conf file for typos and incorrect settings.
• DNS Server Availability: Verify that your chosen DoH server is reachable.

Conclusion:

Enabling DoH on your Fedora system is a straightforward process that significantly enhances your online privacy and security. By following the steps outlined in this guide, you can protect your DNS queries from unwanted surveillance and improve your overall online experience. Remember to choose a trusted DoH provider and regularly review their privacy policies.