DNS over HTTPS (DoH): Securing Your DNS Queries over Port 443

When you type a website address into your browser, the first thing that happens is a DNS (Domain Name System) lookup. This lookup translates the human-readable domain name (like google.com) into the machine-readable IP address (like 172.217.160.142) that your computer needs to connect to the server. Traditionally, this DNS lookup happens over UDP port 53, which is relatively insecure. This is where DNS over HTTPS (DoH) comes in.

DoH, as its name suggests, encrypts your DNS queries and sends them over HTTPS, the secure protocol used for websites. This encryption takes place over port 443, the standard port for HTTPS traffic. This means your internet service provider (ISP), or any potential snoopers on your network, can't see which websites you're trying to access.

Why Use DNS over HTTPS?

The primary benefit of DoH is enhanced privacy. By encrypting your DNS requests, you prevent third parties from monitoring your browsing activity. This is particularly important in situations where:

Your ISP monitors your DNS queries: Some ISPs log and potentially sell your browsing data. DoH prevents this.
You're using public Wi-Fi: Public Wi-Fi networks are often insecure, and DoH protects your DNS queries from eavesdropping.
You're concerned about censorship: DoH can bypass some forms of DNS censorship by routing your requests through a secure, uncensored resolver.

How Does DNS over HTTPS Work?

DoH works by using HTTPS to send DNS queries to a DoH-enabled DNS resolver. The resolver then responds with the IP address (or other DNS records) over the encrypted HTTPS connection. This entire process is hidden from prying eyes.

The process typically involves these steps:

Your browser or operating system sends a DNS query over HTTPS to a DoH server (e.g., Cloudflare's 1.1.1.1 or Google's 8.8.8.8).
The query is encrypted using TLS (Transport Layer Security).
The DoH server processes the query and returns the IP address(es).
The response is also encrypted and sent back to your device.

Configuring DNS over HTTPS

Configuring DoH depends on your operating system and browser. Many modern browsers and operating systems offer built-in support for DoH, or you can manually configure it. Here's a general overview:

Browser Settings:

Check your browser's settings. Many browsers allow you to specify a custom DNS server. You'll need to find the relevant settings and enter the address of a DoH provider (e.g., https://cloudflare-dns.com/dns-query for Cloudflare).

Operating System Settings:

Most operating systems (Windows, macOS, Linux, Android, iOS) allow you to configure your system-wide DNS settings. Look for the network settings and change the DNS server addresses to those of a DoH provider.

Security Considerations

While DoH enhances privacy, it's not a silver bullet. Consider these points:

Trust in the DoH provider: You're entrusting your DNS queries to the chosen DoH provider. Choose a reputable provider with a strong privacy policy.
Potential for censorship: Some DoH providers might censor certain websites or block requests. Consider this if you're concerned about censorship.
Performance: DoH might slightly increase latency compared to traditional DNS over UDP, although the difference is usually minimal.

Conclusion

DNS over HTTPS offers a significant improvement in privacy and security over traditional DNS. By encrypting your DNS queries, it protects your browsing activity from unwanted surveillance. While there are some considerations to keep in mind, DoH is a valuable tool for enhancing your online privacy.