You can force a client to disconnect from a WLAN if they do not obtain a valid IP address within a specified amount of time, in this case, seconds. But in your illustration where you need to force a renew of an IP address, you would need to do this from your DHCP server or from the client. Not all DHCP server support this function nor all clients pay attention to the command. You could, from the ZD force the client to re-authenticate to the WLAN, therefore requesting a new address.
