Public Wireless and DHCP problem

Our Cisco wireless APs use Windows 2008 DHCP. We have Enterprise wireless, secured student wireless and public wireless. On the public wireless, there are many network devices such as iPhone, iPad, and smart phone get IP addresses from the DHCP and the DHCP don’t release those IP addresses  even they already left. Eventually, we will be out of the IP addresses or get a lot bad IP addresses. We have setup DHCP lease time to 1 hour and add more IP pool. But they don’t fix the problem. The only resolution I have is deleting them manually. Does anyone have the same issue and how do you fix it?

Bob Lin, MVP, MCSE & CNE Networking, Internet, Routing, VPN Troubleshooting on

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