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11503 Address Conflict error

After upgrading the primary CSS and putting it back into production the following error mgs started showing up in the sys.log file:

AUG 30 08:24:24 1/1 96 OSPF-1: Address Conflict- fwdAddr conflict with redundant interface address is the VIP address for the front end subnet. I've verified that there is not another device on that subnet with the same IP and I'm not experiencing any problems; however, the reason I upgraded the primary was because we had connectivity issues with the back end servers and when we failed over to the 2ndary those issue went way. The primary is back in production and isn't having any issues except for that error.

The primary CSS is running ( and the 2ndary is running (7.10 Build 305). I'm planning on upgrading the 2ndary next.

Also the sys.log files on both the primary and 2ndary have reached there max 50MB and have stopped logging. I've issued the "clear log sys.log" cmd and it removed the log. Now the sys.log doesn't exist anymore. How can I get logging start again to the sys.log file without rebooting the CSS?

Any help or suggestions would be appreciated.


Cisco Employee

Re: 11503 Address Conflict error

first, let me say that the sys.log file will be created automatically when the CSS will need to logg a new message.

You don't have to do anything.

Then, regarding the issue, could you capture a sniffer trace of the ospf traffic getting into the css complaining about the fwdaddr.