Duplicate IP Address Detection

The controller verifies that its IP address does not match any other network device IP address when you perform either of these tasks:
  • Connect the module to a
    EtherNet/IP™
     network.
  • Change the controller IP address.
If the controller IP address matches that of another device on the network, the controller
EtherNet/IP™
 port transitions to Conflict mode. In Conflict mode, these conditions exist:
  • Network (NET) status indicator is steady red.
  • The 4-character display indicates the conflict.
    The display scrolls: <IP_address_of_this_module> Duplicate IP
    <Mac_address_of_duplicate_node_detected>
    For example: 192.168.1.1 Duplicate IP - 00:00:BC:02:34:B4

Duplicate IP Address Resolution

When two devices on a network have IP addresses that conflict, the resolution depends on the conditions in which the duplication is detected. This table describes how duplicate IP addresses are resolved.
For more information on how to assign IP addresses, see the
EtherNet/IP™
 Network Device User Manual, publication ENET-UM006.
Duplicate IP Address Detection Conditions
Resolution Process
  • Both devices support duplicate IP address detection.
  • A second device is added to the network after the first device is operating on the network.
  1. The device that began operation first uses the IP address and continues to operate without interruption.
  2. The device that begins operation second detects the duplication and enters Conflict mode.
To assign a new IP address to the controller and leave Conflict mode, set the network IP address with the BootP/DHCP EtherNet/IP Commissioning Tool.
  • Both devices support duplicate IP address detection
  • Both devices were powered up at approximately the same time.
Both EtherNet/IP devices enter Conflict mode. To resolve this conflict, follow these steps:
  1. Assign a new IP address to the controller. Set the network IP address with the BootP/DHCP EtherNet/IP Commissioning Tool.
  2. Cycle power to the other device.
One device supports duplicate IP address detection and a second device does not
  1. Regardless of which device obtained the IP address first, the device that does not support IP address detection uses the IP address and continues to operate without interruption.
  2. The device that supports duplicate IP address detection detects the duplication and enters Conflict mode.
    To assign a new IP address to the controller and leave Conflict mode, set the network IP address with the BootP/DHCP EtherNet/IP Commissioning Tool.
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