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New Member

3850 stack problem - duplicate IP

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?

  • LAN Switching and Routing
10 REPLIES
VIP Super Bronze

Can you post the log messages

Can you post the log messages you are seeing?

Do you have duplicate IP address anywhere on your network?

 

 

New Member

They are all like this:Jun 30

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.

 

VIP Super Bronze

ok, find out what port this

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

New Member

The MAC address is actually

The MAC address is actually coming from a port-channel. Tried adding the command but it made no difference.

VIP Super Bronze

Can you also add the same

Can you also add the same command to the other side of the Portchannel?

What type of device is connecting to this 3850?

New Member

It's on both sides of the

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.

 

 

VIP Super Bronze

Yes, put the command on the

Yes, put the command on the physical interfaces and see if it makes a difference.

New Member

I have added this command on

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?

New Member

DOH! Fixed this. Turns out

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.

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