%STANDBY-3-DUPADDR: ????????

[syancy]

I have just started getting these errors on both my MSFC's. I have received these errors on 2 vlans with hsrp running. Here is the log entry:

Jul 30 22:29:07 gmt: %STANDBY-3-DUPADDR: Duplicate address 10.66.44.253 on Vlan900, sourced by 0000.0c07.ac5a

Jul 30 22:30:00 gmt: %STANDBY-3-DUPADDR: Duplicate address 10.66.44.253 on Vlan900, sourced by 0000.0c07.ac5a

I no for a fact that this is not a node that has the same address. PLease Help.

[deilert]

Are these messages constant or just 1 or two after hsrp bounces ? I have seen this when one of the VLANs bounce that has hsrp configured , if the message is not constant I would not sweat it .

[syancy]

That particular vlan was just a couple but earlier in the day I had a vlan do it continuously. This juat began today. So to say the least I am stumped...

[michael_tong]

check the spanning tree. If there is a network loop, this message will occur. I have such experience.

[syancy]

What would cause a loop in this situation? I have no redundant links to a switch that uses this particular vlan.

[milan.kulik]

Hi,

this is the output from the Error Message Decoder:

"1. %STANDBY-3-DUPADDR: Duplicate address IP_address] on [chars], sourced by [enet]

The IP address in an HSRP message received on the interface is the same as the router's own IP address. This condition may be caused by a network loop, a misconfiguration, or a malfunctioning switch.

Recommended Action: Ensure that there are no network loops, check the configuration on all the HSRP routers, and make sure that all switches are correctly configured and functioning properly.

Related document: Cisco - Understanding and Troubleshooting HSRP Problems in ... "

I suppose 0000.0c07.ac5a is your HSRP group virtual MAC adddress. So I think there might be a loop in your network causing the HRSP router to receive packets originated by itself.

Regards,

Milan

[ttuncaral]

According to CCO document

http://www.cisco.com/en/US/customer/tech/tk648/tk362/technologies_tech_note09186a0080094afd.shtml

Troubleshooting HSRP Case Studies chapter contains information about your problem.

this is a normal message for HSRP configurations and it can be suppressed by using an ACL.

Regards,

[milan.kulik]

If you read the document carefully it doesn't say "it's a normal message". It says:

"These error messages do not necessarily indicate an HSRP problem. Rather, the error messages indicate a possible Spanning Tree Protocol (STP) loop or router/switch configuration issue. The error messages are just symptoms of another problem."

And

"Furthermore, there is a method to prevent the active router from receiving its own multicast hello packet by using an access-list. This is only a work-around for the error messages however. This work-around actually hides the symptom of the problem."

So ACL only suppresses the error messages bot doesn't fix the problem.

Regards,

Milan