HSRP failover activated by ip helper-address change via ?

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Oct 5th, 2009
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I recently had an incident where immediately after issuing the "no ip helper-address" command on a 6506 switch, the switch became unresponsive and traffic reached the standby switch. Some colleagues have speculated that this was caused by the command, or my failure to specify an ip address in the command (I wanted to remove the single ip helper-address from the interface, or because I ssh'd to the switch via the standby ip address.

I have no doubt that there is a link between running the command and a failure happening. However, I'd like to know if anyone thinks a failover situation is likely when running the above command.

If it isn't a direct cause of running the command, any suggestions on how to figure out what caused the failover? We recovered the switch by reloading.

Many thanks,


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xcz504d1114 Mon, 10/05/2009 - 13:56
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There should be no correlation with the 2. I have seen similar cases where creating a single span port on a 6509 caused a similar problem, mine turned out to be hardware failure, reatable everytime, took a reload to fix it.

I would look for IOS bugs and hardware faults.



blindmind Mon, 10/05/2009 - 14:09
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Thanks for the reassurance. So a config change can on occasion cause a crash? I'll check the IOS version and see if I can find any bugs listed anywhere that might shed some light.

glen.grant Mon, 10/05/2009 - 14:56
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It shouldn't cause a hang or crash , if it does it's a bug . The only thing that could have happened if you accidently did a "no ip address instead of the helper and I sm sure would have known if you did that . I have never seen that on a 6509 before and we do it occasionally.


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