zlacker

If you hover your mouse over an ad linking to sketchy-service.com ... then the remote dns host for sketchy-service.com now has your IP address.

>>tracke+(OP)
That seems neither here-nor-there for the 1.1.1.1 service.

Doesn't the browser's internal resolver use an external recursive server (either the host's configured ones or browser-determined ones)? Chrome does, AFAICT. As opposed to being a recursive resolver itself, it just implements a caching stub resolver.

The remote DNS host for sketchy-service.com doesn't see your IP address, they see the recursive server's address.

>>tracke+(OP)
Browsers can also prefetch pages under some circumstances (I'm not sure of the details). In that case, the web server for sketchy-service.com now has your exact IP address (vs. the truncated address encouraged by this extension). In firefox this can be prevented with:

network.dns.disablePrefetch True

network.prefetch-next False