Embedded DNS disable forward?

Hi all,
I have problems with embedded DNS, it is working fine but my DDC is firewalled and some containerized applications are trying to access the world for updates (in fact my applications try to use the latest apt cache updates for example, even if packages are already installed they try to check if they are updated…). I have deployed my containers without problems on isolated DDC but real problem comes when deploying on firewalled DDC but with internet resolution, and that situation leads us to very long times to reach timeouts…
We are using embedded DNS on, but it forwards to hosts DNS.
Is there any way to disable embedded DNS forwarding?
Many Thanks,
Javier R.