WCS Controller detected duplicate IP address

[nathan.ollis]

We recently upgraded WCS to 7.0.240 and our WLC's to 7.0.230.  Since then WCS comes up with a critical error of "Controller 'X.X.X.X' detected duplicate Ip address 'X.X.X.X' being used by machine with mac address 'Xx:xX:xX:XX:XX:XX'."

This make correlates on a few to the MAC of the management/user interfaces.  I attempted to change one of the addresses.  Was hoping if I freed it up I could figure what device was trying to use it also, but nothing ever wanted the address.  It is more of an annoyance that I cant figure it out, everything is still working like normal.  I tried doing searches and found people with ap-manager and management in different subnets, all of ours are on the same subnet.

Any suggestions?

Thanks!

[c.andrew]

I've seen similar in the messages logs on a WLC. It turned out to be two LAPs with the same IP address so it was fairly easy to track down.

In your case, you need to find the offending second device. Have you tried to located the offending MAC address using show arp and show mac addresss-table on your switches (assuming you can do this)?

I've also used Linux with some success to track down duplicate addresses. Linux has a very handy arping command which reports MAC addresses for the specified IP. Duplicate IPs/MACs are very easily spotted - but you're still faced with tracking them down.

[Scott Fella]

I have seen this too and recent with new code, but its not the code:)  The issue was also that the customer didn't reserve the ip address of access points, so clients where getting dhcp address from the dhcp server.  Also, I had customer use static address on devices that were being used for the WLC and or access points.  

What I did, was enable dhcp required on all the WLAN's and noticed that most of the errors went away.  Then you can go back and find those devices, because someone will complain.  Make sure that the dhcp scope has the ip address excluded and or using mac reservations for AP's if possible.  

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Scotty

[nathan.ollis]

It started happening when we recently updated the WLC and WCS.  The majority of them cleared, except one test controller we have setup.  It is the controller on test VLANs created, with 1 or no APs...there is nothing else in the ranges.

The end "being used by machine with mac address '00:27:0d:df:XX:XX" that MAC address is the MAC of the controller interfaces...

That is why I am so confused.  I have done ping scans, looked through DHCP, I even took the controller down and waited on something to grab the IP...nothing ever did.

[Scott Fella · Accepted solution]

v7.0.250.0 is the latest code. If nothing is affected, then maybe it's a bug. You can try to upgrade the WLC code or else open a TAC case and see if that is a known issue. Have you used the bug search tool to see if that comes up?

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Scotty