Afnic, the association responsible for the .fr top-level domain, has released a free software tool called IBDNS (Intentionally Broken DNS) to intentionally deviate from DNS specifications. This tool is designed to improve the accuracy and reliability of the DNS zone health assessment tool, Zonemaster. By simulating incorrect behavior of authoritative name servers, IBDNS aims to help Zonemaster provide accurate diagnostics in all scenarios. Afnic invites developers, security auditors, researchers, and anyone interested in DNS technology to explore the source code of IBDNS on their Gitlab server. Afnic also plays a significant role in managing various French overseas and generic TLDs.
https://www.afnic.fr/en/observatory-and-resources/news/afnic-launches-ibdns-the-intentionally-broken-dns-server/