06-30-2014 06:42 AM - edited 03-07-2019 07:52 PM
I have a 3850 stack running ip services on version 03.02.03.SE of IOS-XE. I have multiple SVI's on the stack and getting duplicate ip address messages in the logs.
I have checked that the stack has come up properly and they are both reporting ready and are active/standby. I have recreated the stack a couple of times and each time its the same.
Any ideas? Bug maybe?
06-30-2014 06:55 AM
Can you post the log messages you are seeing?
Do you have duplicate IP address anywhere on your network?
06-30-2014 06:58 AM
They are all like this:
Jun 30 13:55:41.568: %IP-4-DUPADDR: Duplicate address x.x.x.x on Vlan6, sourced by <MAC address>
The IP address of the interface is not used anywhere else on the network, as they were reserved for this building. The only place the IP address exists is on the SVI on the stack.
06-30-2014 07:04 AM
ok, find out what port this mac address is coming from, then go under the physical port and add this command
nmsp attachment suppress
then clear the log and test again.
HTH
06-30-2014 07:17 AM
The MAC address is actually coming from a port-channel. Tried adding the command but it made no difference.
06-30-2014 07:52 AM
Can you also add the same command to the other side of the Portchannel?
What type of device is connecting to this 3850?
06-30-2014 08:12 AM
It's on both sides of the port channel which is trunked. Does it need to go on the physical interfaces that are in that vlan?
Basically it's a 3850 stack running ip services connected to a larger 3850 stack running IP Base.
06-30-2014 08:34 AM
Yes, put the command on the physical interfaces and see if it makes a difference.
07-01-2014 02:49 AM
I have added this command on all the physical ports on both stacks. Still getting the duplicate address messages in the log.
Anything else I can look at? As I say, the stack looks fine and the IP addresses it is complaining about only exist on the SVI on the ipservices stack.
There is a newer version of IOS-XE that is recommended on the Cisco site. Should I go for this?
07-01-2014 03:44 AM
DOH! Fixed this. Turns out someone put the SVI on the ipbase stack thinking it needed to be there. Removed them and its now sorted. Thanks for the assist.
05-10-2017 03:03 AM
Hi,
I have similar problem. Two switches WS-C3850-24T in stack, (IOS-XE Version 03.02.03.SE).
On downlik switches on uplinks we get this duplicate info message.
After disabling IP Device Tracking (IPDT) with command:
it helps:
http://www.cisco.com/c/en/us/support/docs/ip/address-resolution-protocol-arp/118630-technote-ipdt-00.html
Thanks for help!
Michal
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