====== Windows Radom IP Conflict Solution ====== ===== The Problem ===== * Every so often I would get a IP conflict with **0.0.0.0** and a message like this one The system detected an address conflict for IP address **0.0.0.0** with the system having network hardware address CC-D8-C1-10-E8-19. Network operations on this system may be disrupted as a result. When I looked up the mac address it would point to a Cisco device which is particularly strange since I have only to cisco devices in my entire network. * Anyway the issue is apparently that when Windows NT 4 and higher binds a IP address it check to see if the address is taken even if that address is **0.0.0.0**. Normally this shouldn't be a problem, but initially Windows apparently binds **0.0.0.0** before it binds it's real address. So what's the problem you might be asking well certain cisco switches and routers will reply to ARP requests for **0.0.0.0** which has the effect of causing a IP conflict scenario on Windows causing the detecting interface to be disabled. * **So long story short Microsoft and Cisco both did something that either one didn't expect** ===== The Saga continues ===== * Cisco has kindly provided a very nice KB article to fix this issue at this [[http://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/8021x/116529-problemsolution-product-00.html|Link]] * Unfortunately for me I didn't have access to the Cisco equipment that was causing the issue ===== Solution ===== * Lucky if you don't have access to your cisco equipment there is a registry tweak to fix the issue Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Tcpip\Parameters] "ArpRetryCount"=dword:00000000