DNS is one of the core protocols for web communication. The protocol is used to communicate with DNS servers which translate the human-readable domain name of a website into the machine-readable IP address that your computer needs to use to communicate with the right web server.
Unfortunately, DNS doesn’t use encryption which means that it’s possible for someone to listen in to your DNS requests and work out what websites you’re browsing to. DNS only involves the domain name of a website, so it wouldn’t be possible to work out exactly what page you were browsing to, but a domain name can be enough to disclose something private. For example, accessing a medical website may disclose that you or someone you know likely has an illness or even a specific type of illness. Similarly, accessing a travel website could indicate that you’re planning on going on holiday soon, or a bankruptcy lawyer could indicate you’re on the verge of bankruptcy.
DoH, or DNS over HTTPS, is an upgrade to the DNS protocol that initiates an encrypted HTTPS connection to the DNS server before using that secure HTTPS connection to make the DNS request. The encryption of the HTTPS connection provides you with as much security as the rest of your web traffic.
The HTTPS protocol is the standard protocol for encrypted web traffic. It automatically negotiates the strongest supported encryption for the connection between your device and the webserver.
How to enable DoH in Firefox
To enable DoH in Firefox, you first need to open Firefox’s settings. To do so, click on the burger menu icon in the top-right corner, just under the “x” icon, then click “Options”.
In the “General” tab of the options menu, scroll all the way to the bottom and click on “Settings”. In the connection settings popup, click on the bottom checkbox, labelled “Enable DNS over HTTPS” then select a provider from the “Use Provider” dropdown box. Once, you’ve made your choice of provider click “OK” to save the change.