..to put it short: get that dhcp server out of your dmz box and into a lan box (or maybe the firewall).
..the dmz is _only_ for stuff you want me, Saddam, Osama bin Laden, Bill Gates, the scriptkiddies and the FBI to see. Here, I speak with authority; Neither of us needs your dhcp server. ;-)
Hey, who said you don't need our DHCP server? I raised it up with love, since it was just a little Debian package! It has very good manners and I tought him to respect every legal request, no matter from which OS it came. :-)
But seriously: I got your point and will reconsider our network layout.
Thank you for your advice, Carsten.