Thank you for your reply devorem. I configured my Endian Firewall using that manual. But it doesn't explain how to ONLY hand out fixed leases - or is there something I don't get right?
I have to activate the DHCP in order to get fixed leases working, then the next fields are Start end End Adress. If I leave them blank, the DHCP will hand out all existing IP adresses in the subnet. So I set the start and end adress to the same IP and configured the fixed leases. But as far as my understanding goes that leaves this one adress to be handed out to any PC connected which has not been assigned a fixed lease through its MAC adress.
Maybe the only way to do that ist through the custom confguration line - I'll read the documentation attached to that.
If anyone could help me figure out the correct options it would certainly save me a lot of time