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New Member

HSRP Flapping on 6500's

have two Cat. 6500's with dual MSFC's gig/etherchannel together. All vlans are running HSRP between MSFC's. Every 4 hours (give of take a couple min) the standby MSFC goes active on all vlans, thus causing a Duplicate Address as the active MSFC never goes into Standby state. Has anyone experienced this type of behavior? Any ideas on how to troubleshoot??

New Member

Re: HSRP Flapping on 6500's

We had two MSFC's in the one chassis both active running HSRP between them. All HSRP groups were default hence 0000.0c07.ac00 was used on all VLAN's. The problem was we could not isolate to the VLAN where the problem originated. Try using a different stand-by group per interface to force HSRP to use unique MAC addresses. If you continue to get the duplicate, then you qualify for the next fault where the box stopped forwarding some multicasts. Just the simple multicasts like HSRP (to start) then OSPF. Cisco replaces the entire chassis to ensure the machine had identical software, firmeware and hardware releases. Get escalated help with this now.

Cisco Employee

Re: HSRP Flapping on 6500's

Check out the following troubleshooting document: