Opening this as a feature request.
- Pi-hole version is v5.2.4 (Latest: v5.2.4)
- AdminLTE version is v5.3.2 (Latest: v5.3.2)
- FTL version is v5.6 (Latest: v5.6)
- OS and version: Ubuntu Server 20.10
- Platform: Raspberry Pi 4
Add multiple IPv6 entries for one and the same domain.
Actual behavior / bug
An error message is thrown that an IPv6 for that domain already exists.
As multiple IPv6 addresses for one interface are a core concept of IPv6, Dnsmasq will also allow multiple addresses in general. The restriction in Pi-Hole is a blocker if you are heavily relying on reverse-lookups of IPv6 addresses. I would consider this as a bug, since it is against standards. I'm currently working around this by editing the file without GUI.
Solution should be simple: remove the duplicate check for IPv6. Everything else is already proper handled by Dnsmasqs core with hosts files.