02-11-2007 06:50 PM - edited 03-05-2019 02:17 PM
Anyone have faced this log message of duplicate IP address before?
Here is the network topology
C6509CS01 --------------- C6509CS02
---------------
This problem occured for 5 min and brought the customer vlan 1 network. Note that the
C6509CS01
Feb 8 08:08:32: %STANDBY-3-DUPADDR: Duplicate address 10.1.1.253 on Vlan1, sourced by 0000.0c07.ac09
VLAN 1 MAC address on C6509CS01
Vlan1 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 0009.b63e.cffc (bia 0009.b63
C6509CS02
*Feb 9 01:29:49: %STANDBY-3-DUPADDR: Duplicate address 10.1.1.252 on Vlan1, sourced by 0009.b63e.bffc
VLAN 1 MAC address on C6509CS02
Vlan1 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 0009.b63e.bffc (bia 0009.b63e.bffc)
Internet address is 10.1.1.252/24
I am suspecting this is a spanning tree loop and causes the switch to see a duplicate IP address. But logically, there is no loop between the 2 6509 unless the port-channel connecting the 2 switches fail and in turns there is a loop. But in this cases, STP should kick in.
Anyone have any solution?
02-11-2007 07:00 PM
What version of IOS? There are some nasty Etherchannel bugs in 12.2(17)SX and earlier code where the switch reflects packets back to itself.
-Brad
02-11-2007 07:19 PM
The switches are running in hybrid mode.
Here are the IOS versions
CatOS: 7.1(2)
MSFC: 12.1(11b)E
02-11-2007 07:43 PM
check your HSRP configuration.
02-11-2007 08:00 PM
I've heard of this happening when multiple non-Cisco Wireless Access Points (Symbol specifically) were connected to 6500s and they didnt hand off a roaming client fast enough / properly ... so the switch would see the same MAC on two diffeent ports at the same time.
I think it also may show up as port flapping.
Other than that, I haven't seen / heard of it.
Good Luck
Scott
02-15-2007 10:58 AM
That is HSRP configuration issue. Make sure
your HSRP group numbers on both routers match.
HTH,
Oleg
02-18-2007 04:08 PM
As said above check your etherchannel configurations. I had a similar problem when upgrading from hybrid to Native on two 6509s.
I had set one side to 'on' and the other to 'desirable' and I got the same error messages, and it brought everything down. Once we changed both sides to 'on' everything was fine. I don't think it is an HSRP problem, it is an STP problem as you say, it is seeing its own hsrp multicasts many times over.
06-25-2007 06:59 PM
There is a loop caused by bad etherchannel.
Unplug the cable of etherchannel, clear configurations related with etherchannel,and config again.Be carefule the mode of channel shuld be desired non-silent, it will scalible.
Thanks
Li song
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