Roadwarrior unable to resolve local Host Names through IPsec Tunnel

[kgd192]

Hi,

I set up an IPsec server following the official guide (https://docs.opnsense.org/manual/how-tos/ipsec-swanctl-rw-ikev2-eap-mschapv2.html).
All is well, I am able to access the Internet via the Tunnel as well as the Opnsense Firewall Interface using its own local hostname. However the Roadwarrior cannot resolve the local host name of my server and therefore not use any of its services. I suspect my phone is not using Opnsense as the DNS server, how am I able to enforce this?

Thanks in advance, Kai