Note: this post has been updated to fix a mistake in the knot-resolver configuration. The earlier version would not have provided the privacy it purported to. I regret the error.
Until yesterday I hadn’t thought too much about DNS metadata leakage. Here’s how it works: your computer sends out a request to resolve a DNS hostname, let’s say “topsecretwebsite.example,” and your DNS server responds back with its IP address in a way that’s easy to eavesdrop on. It’s wild that the Internet works like this by default.
What happened yesterday is a company called CloudFlare (a popular and free content delivery network) announced a new DNS service at the IP address
18.104.22.168. (Yes it launched on April 1, no it’s not a joke.) The service supports a couple of interesting privacy protecting options: DNS-over-HTTPS and DNS-over-TLS. Those technologies don’t guarantee your DNS lookups are accurate (check out DNSSEC for that), or that the DNS provider won’t someday betray you, they just make it’s harder to collect metadata by listening in on DNS’s cleartext port 53.