Arch Linux and DNS-over-HTTPS (DoH): A Comprehensive Guide

DNS-over-HTTPS (DoH) enhances your online privacy and security by encrypting your DNS queries. This guide provides a detailed walkthrough of setting up DoH on your Arch Linux system, covering various methods and considerations.

Understanding DNS-over-HTTPS

Traditionally, DNS queries are sent over UDP or TCP, making them vulnerable to eavesdropping and manipulation. DoH encapsulates these queries within HTTPS requests, leveraging the security and encryption provided by TLS. This prevents your ISP and potential network attackers from seeing which websites you're accessing.

Choosing a DoH Provider

Selecting a reputable DoH provider is crucial. Consider factors such as privacy policy, location, and performance. Popular options include:

• Cloudflare (1.1.1.1): Known for its speed and strong privacy policy.
• Google Public DNS (8.8.8.8): A widely used and generally reliable option.
• Quad9 (9.9.9.9): Focuses on security and blocking malicious domains.
• CleanBrowsing (various options): Offers different filtering levels, from family-friendly to security-focused.

Each provider has its own advantages and disadvantages. Research each option thoroughly before making a decision based on your specific needs.

Setting up DoH on Arch Linux

Method 1: Using systemd-resolved

systemd-resolved is the recommended DNS resolver for Arch Linux. This method is generally the easiest and most integrated.

1. Edit /etc/resolv.conf: This file should contain only the line nameserver 127.0.0.53. If it doesn't, create the file or modify it accordingly. This points your system to systemd-resolved.
2. Edit /etc/systemd/resolved.conf: Add or modify the DNS= option to specify your chosen DoH provider. For example, for Cloudflare, add: DNS=cloudflare-dns.com or DNSOverTLS=cloudflare-dns.com or DNSOverHTTPS=https://cloudflare-dns.com/dns-query. The optimal option will depend on the specific provider and might involve using their respective URL addresses.
3. Reload systemd-resolved: Run sudo systemctl reload systemd-resolved.
4. Verify the configuration: Use systemd-resolve --status to check if DoH is correctly configured.

Method 2: Using NetworkManager

If you manage your network connections through NetworkManager, you can configure DoH within its settings. The specific steps may vary slightly depending on your desktop environment, but generally involve accessing NetworkManager settings and specifying the DoH server address under the IPv4 or IPv6 settings for your connection.

Method 3: Manually configuring your applications

Some applications allow you to specify DNS servers directly. Check your application's settings for options to configure custom DNS servers. This method only affects the specific application, not your entire system.

Troubleshooting

If you encounter issues, check the following:

• Firewall rules: Ensure your firewall allows communication on port 443 (HTTPS).
• systemd-resolved status: Use systemd-resolve --status to check for errors.
• Network connectivity: Verify your internet connection is working correctly.

Conclusion

Implementing DoH on your Arch Linux system significantly enhances your online privacy. By following these steps and choosing a reliable provider, you can enjoy the benefits of encrypted DNS queries, adding an extra layer of security to your browsing experience. Remember to always keep your system updated and regularly review the security practices of your chosen DoH provider.