iOS 5.0.1 wireless Bug - DHCP

We discovered an interesting issue yesterday on our network, and upon much searching, I didn't see anyone else with the same conclusion.

Allow me to start by describing the issue. It's happened on a few occassions in our network over the past several months (we recently started allowing Apple iOS devices on our network as Exchange Activesync clients), but I was finally able to narrow it down today.

Issue: Certain iOS devices when connected to the wireless network retain their DHCP Lease from their home network in the background, while connecting to the business network with a like subnet. The IP Address that the iOS device is retaining from home is NOT in the DHCP scope of the business network, but conflicts with a static assigned IP Address on one of the corporate network services (i.e. Print Server, Email Server, File Server, Database Server) in the like subnet. For example "User A" running an iPhone 4S with iOS 5.0.1 has an Airport Extreme at home that assigns DHCP Addresses in the 10.0.0.x scope. The Corporate DHCP Scope is 10.0.4.x-10.0.5.x with similar subnet. "User A" connects to corporate network via wi-fi and is assigned an IP address of 10.0.4.x (but in the background the device is reserving 10.0.0.x from home Airport Extreme.) Address 10.0.0.x belongs to back-end email server, and whenever "User A" turns their device on, it disrupts the network connectivity for the rest of the corporate network to the email server. "User A" turns off wi-fi on iPhone, and normal corporate network operations resume. In the past, the issue has conflicted with a less major server, or another windows client, and so a resolution was able to be acquired by renewing the IP Address on the Windows client computer.

The issue presents it self as one of our Windows Server machines complaining about an IP Address Conflict on the network. Upon examining the Windows Event Viewer in the System Log, we discover an error message from the "Tcpip" service "The system detected an address conflict for IP address 10.0.0.X with the system having network hardware address 60:C5:47:XX:XX:XX. Network operations on this system may be disrupted as a result." Upon examining the mac address beginning with 60:C5:47 we discover this particular MAC Address range belongs to Apple Inc. (LINK) This led us to search the building for the offending iOS device on which we were able to verify the Wireless MAC address.

In a similar forum post by a user in 2009, the suggestion was that the issue lay with the Windows computer. Well, in that particular case, it was a Home PC, and the user was able to 'work-around' the bug by renewing their DHCP lease on their other client that was reporting the issue. In our case, since the conflict occurs with a Network Server with a staticly assigned IP and services / certificates assigned to that interface, it's not as easy as renewing the IP address to allow the Windows computer to 'fix' the issue. I believe the issue lies in the iOS wireless driver, and needs to be addressed by Apple Development team. I'm not sure the best way to accomplish this, so I figured I'd start in the support forum. Since there wasn't a forum for iOS, I placed the issue under iPhone for Enterprise, though this issue is reproducable with iPad and iPod Touch also.

Here's a detailed post by Princeton University where they describe the issue in great detail. http://www.net.princeton.edu/apple-ios/ios41-allows-lease-to-expire-keeps-using- IP-address.html#chronology How can we get greater urgency to get this bug fixed?

I'd appreciate response / suggestions / input / feedback.

Thanks!
DRO4LIFE