Enabling and Configuring DNS over HTTPS (DoH) in Firefox for Android

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 explains how to enable and configure DoH in Firefox for Android.

Understanding DNS over HTTPS

Traditionally, DNS queries are sent in plain text, making them easily intercepted. DoH solves this by sending these queries over HTTPS, the same secure protocol used for browsing websites. This adds a layer of encryption, protecting your privacy.

Enabling DoH in Firefox for Android

Unfortunately, Firefox for Android doesn't have a built-in, easily accessible setting to directly enable DoH like the desktop version. The process involves using a custom configuration.

Method 1: Using about:config (Advanced Users)

This method requires accessing Firefox's advanced settings, which should only be done if you understand the implications. Incorrectly modifying settings can cause problems.

Open Firefox for Android and type about:config in the address bar.
You'll see a warning; accept the risk and continue.
Search for network.trr.mode. If it doesn't exist, you might need to create it (Right-click, New -> Boolean).
Set network.trr.mode to 2 (for automatic DoH selection based on your regional settings) or 1 (for custom DoH server - see below).
If you chose 1, you also need to set network.trr.uri to your preferred DoH server address (e.g., https://cloudflare-dns.com/dns-query or https://dns.google/dns-query).
Restart Firefox for a change to take effect.

Important Note: Using about:config incorrectly can potentially break your browser. Proceed with caution.

Method 2: Using a Custom DNS Provider (Recommended for Simplicity)

Several Android DNS apps offer DoH capabilities. These apps often provide a simpler and safer way to enable DoH compared to manual configuration within Firefox.

Example: Search the Google Play Store for "DNS over HTTPS" or "private DNS". Many reputable apps provide this functionality.
Once you've installed and configured such an app, it will generally handle DoH transparently; you might not need to change any settings within Firefox itself.

Choosing a DoH Server

Several reputable providers offer DoH services:

Cloudflare: https://cloudflare-dns.com/dns-query
Google Public DNS: https://dns.google/dns-query
Quad9: https://dns.quad9.net/dns-query (focuses on security and blocking malicious domains)
CleanBrowsing: Offers various filtering options. Find their DoH endpoint on their website.

Consider factors like privacy policy, security, and performance when selecting a DoH server.

Verifying DoH is Enabled

After configuring DoH, you can verify it's working by checking the network settings in Firefox's about:networking page. However, this might not always show DoH explicitly, depending on how the connection is established.

Troubleshooting

If DoH isn't working, check the following:

Correct configuration: Double-check your about:config settings (if used) for typos.
Server availability: Ensure your chosen DoH server is online and accessible.
Network restrictions: Some networks might block DoH connections. Try connecting to a different network for testing.
App conflicts: If using a third-party DNS app, ensure it's properly configured and not conflicting with Firefox settings.

Disclaimer: This information is for educational purposes only. Incorrectly configuring your browser settings can lead to issues. Always back up your data and proceed with caution.