Dismail.de Secure DNS is a free DNS resolver with filtering of advertising, tracking and malware domains. It runs two resolvers (fdns1 and fdns2) that offer DNS over TLS on port 853 and DNS over HTTPS at the /dns-query path; the website also lists SPKI pins and configuration profiles for iOS 14 and later. The filter is built from public blocklists, including StevenBlack, Disconnect, EasyList/EasyPrivacy and OISD. According to the operator, the resolver works without user logging and does not redirect mistyped domain names for marketing.
The service is run by an individual operator, Stefan Sieg, in Münster, Germany, and therefore falls under German and European law. The servers run on Hetzner Online infrastructure, on OpenBSD or FreeBSD with full disk encryption. There is no non-European parent company. The service's source code is not published as open source. Because this is a personal project funded by donations, it suits individuals and small organisations looking for a European filtering resolver, and less so situations that require contractual guarantees.