Not enough info... but I'll take a guess. A ZoneDirector is a WLAN controller hanging off your network,
and is designed for use with an Internet Router, DHCP server, FireWall, etc on your LAN. You should
use switches that can support VLANs, so you don't let client devices on your ZD/AP network.
But if you "trust" everyone not to try and get into your ZD, you *can* use the built-in DHCP server (meant
mostly for AP addresses, but can support Clients too if you don't assign a VLAN other than 1, in your
WLAN configuration.
The /24 subnet that the ZD is in, can be used for DHCP (from Configure/System/DHCP Server) and is
limited to 254 IP addresses, of which one must be your ZD and one must be your Def-GW Router.