Client IP Address conflicts

[Scheerer]

I keep seeing alerts for IP address conflicts between 2 MAC addresses although when I check none actually exist.

In the Meraki portal there are indeed 2 devices showing with the same IP address, although when I check the devices, they actually have 2 different IP addresses.

I have a colleague that has also experienced this issue and I am wondering if anyone else is seeing these alerts and cannot trace a cause?

[PhilipDAth]

I have not seen this happen myself - unless there really is an IP address conflict.

I assume there is no chance there are two DHCP servers on the LAN?

Are both devices configured to use DHCP, or is one/both using a static IP address?

[MilesMeraki]

You could try and take a packet capture from the LAN side of your Meraki device to ensure that there is differently not an IP Conflict issue. Trying rebooting your Meraki device to clear any ARP cache or alternatively you may have to wait for it to clear itself.

You could also attempt clearing the client usage data (If you're using an MX device) by following this guide - https://documentation.meraki.com/MX-Z/Monitoring_and_Reporting/Clearing_client_usage_data_on_the_MX_...

[Pierrot]

We had a similar case generating alerts.  A Thinkpad with Ubuntu.  DHCP was assigning an IP to both NICs, wifi and ethernet.  But if I understand correctly, the MX100 was also attributing both IPS to each NIC, resulting in alerts.  Mind bending.

[SergioAtVan]

Experiencing the same as Pierrot..Thinkpad with Ubuntu....

MX is alerting "The IP xxxxx is claimed by clients with the following MAC addresses: <wifi mac>  <wired mac>".

Is the MX finding the device name and then complaining when there is a DHCP request using another media coming from the same hostname? 

[Yourguide32]

I know this is a very old post, but I am experiencing the same or similar with an Ubuntu Server.  The Meraki alert is attributing the MAC address from each of the two NICs to the same single IP address we have assigned in the DHCP server to just one of the NICs.

I know this has something to do with "teaming" as we attempted to team the NICs on this system, but did not ever get it to complete fully.   I suppose the alerts are evidence that some sort of teaming may be occurring since its detecting the MAC address change and alerting us. 

I don't really have a solution yet, but this post has pointed me in the right direction. Thanks.