@leonroy said in Can't create IPv4+IPv6 Firewall rule with an alias:
What I ended up doing was sticking my PiHole IP address in an Alias as well and setting that as the Source alias. Not sure if that's the best way of doing it but it worked...
If your PiHole should answer IPv6 and work with IPv6 it needs an IPv6 address. Without that makes no sense, then you can simply block all IPv6 alltogether. If your Pi has IPv4 and IPv6 then that's the right way, put both into the alias and use it in rules.
That said I wouldn't work with invert rules but that's my approach.