See https://github.com/n1trux/awesome-sysadmin#dns
* [CoreDNS](https://coredns.io/) - Plugin driven DNS Server with support for proxying to Google's DNS-over-HTTPS. ([Source Code](https://github.com/coredns/coredns)) `Apache``Go`
* [nsupdate.info](https://www.nsupdate.info/) - nsupdate.info is a dynamic DNS service. ([Demo](https://www.nsupdate.info/account/register/), [Source Code](https://github.com/nsupdate-info/nsupdate.info)) `BSD``Python`
* [SPF Toolbox](http://spftoolbox.charlesabarnes.com) - Application to look up DNS records such as SPF, MX, Whois, and more. ([Source Code](https://github.com/bulbajackel/SPFtoolbox)) `MIT``PHP`