Pihole, VLANs & VPN

[yubiuser]

I also route traffic from different VLANs to pihole.
But you could also add virtual interface to your device hosting pihole for every VLAN

Secondary VLAN resolving DNS query without PiHole

That's because you are doing it wrong! Don't route DNS Traffic from VLAN to VLAN but instead add some VLAN Interfaces to your Pi-Hole Server so it has a simple local connection with every Client in each VLAN If you want I can write up a Tutorial for this in English ? In case you speak Dutch or feel like using Google Translate then click here : https://gathering.tweakers.net/forum/list_message/57865570#57865570