1756-ENBT Duplicate IP at Random

Hello All, I have a ControlLogix system setup on a wireless network. The topology allows 3 clients (Moxa AWK-6222) which are connected to simple unmanaged switches at 3 different locations. Each of these switches consist of the client radio, a 1756-ENBT in a Logix chassis, and a Proface HMI. Each of the clients talk to 4 other access points (Moxa AWK-6222) within the range of the system. All Moxa radios are configured for "Redundant Wireless" with two separate SSID's. All access point radios also connect to a common switch going back to our main servers.

My issue: This system was recently upgraded to the dual redundancy wireless Moxas from a Cisco wireless system within the month. The system operates without issue for sometimes a day or two, but then I get an error on one of the ENBT modules "Duplicate IP - xx:xx:xx:xx:xx:xx". All ethernet devices are configured to be static and I have ensured that I have used available addresses on the subnet. I have scanned the subnet with an IP scanner and have found that the MAC address of one of the Moxa clients will get assigned to everything connected to the switch it is connected to. For example, the PLC, HMI and client will all show the same MAC. I know they are not, but it shows up that way nonetheless. This issue will clear itself if I cycle power to everything on the switch.

I've read a couple posts in other places with similar issues, but nothing was resolved. Please help if you can.

Thanks,
SJHunn

When strange things happen try updating the firmware on all devices.

Thanks for the reply. We have like minds. I have already verified the 1756-ENBT firmware and have discussed this issue with the Moxa service dept. Moxa has replied that they have identified the issue as being inherent of an AP-Client as MAC Spoofing in their system and are looking into a firmware fix or a work-around for use with these Allen-Bradley components. I'll keep everyone posted as to the status of this issue. Thanks, SJHunn