ISD 820 Knowledge Base

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====== 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 <file>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.</file>  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
<file reg ip_conflict_fix.reg>
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Tcpip\Parameters]
"ArpRetryCount"=dword:00000000
</file>
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