BUG: DHCP Client Receives Duplicate IP Address (190534)

SYMPTOMS

The client receives an error message that an IP address conflict has been detected on the network: the local interface has been disabled. TCP/IP has not initialized properly, and network communication through TCP/IP is not possible.

The client computer receives the following error message:

The system has detected an IP address conflict with another system on the network. The local interface has been disabled. More details are available in the system event log. Consult your network administrator to resolve the conflict.

The following error message appears in the system event log:

The system detected an address conflict for IP address x.x.x.x (where x.x.x.x is the conflicting IP address) with the system having network hardware address yy.yy.yy.yy.yy.yy (where yy.yy.yy.yy.yy.yy is the hardware or MAC address of the other client). Network operations on this system maybe disrupted as a result.

CAUSE

In this case, 2 different clients, by chance, used the same XID. The transaction ID (XID) is used to track each configuration sequence. Any response to a DHCP Discover packet should reference the same XID.

Because 2 clients did send a DHCP Discover with the same XID at nearly the same time, the DHCP initialization sequence (Discover - Offer - Request - Ack) was completed by both in the same way, resulting in the error messages above.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.51 and 4.x. A supported fix is now available, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.