Outgoing Problems with 1x WAN + 1x OPNVPN Client to feste-ip.net: DNS broken?

[fdiskc2000]

Hi there,

i´m getting mad with my problem. Perhaps anyone can push me to the right direction, because i´m an absolut beginner with opnsense.

Actually:
Internet-Router is a Fritzbox 7490 which is managing my actual home network (192.168.178.0). There is a piHole DNS inside this network, provided as DNS by Fritzbox-DHCP.
My opnsense (18.7.4) is a client within this network, connected with WAN @ DHCP.
There is also a LAN-Interface (Standard 192.168.1.0) with some clients for testing.

The opnsense itself is connecting to feste-ip.net to get a fixed IPv4 by VPN-Tunnel, which is connected and traffic comes in.

Problem:
When the VPN Client (TUN-device) is connected, the opnsense seems to have DNS Problems, as opnsense update, traceroute etc. doesn´t work or need veeeeeery long time.
I don´t want traffic to go out the VPN for now, but seems the firewall wants to go this way?
Firewall Rules blocking traffic from LAN -> VPN don´t work.


What am i missing?
Many thanks for some help.