Duplicate IP
Event is displayed when two IP addresses that are identical, from different hardware devices, are seen on your network.
This indicates that duplicate IP address (that is the same IP address as source on two different source MAC addresses) was found.
Possible reasons for the event:
a) A mixture of static IP addresses and DHCP is being used without limiting the scope of the DHCP server's address table.
b) A user has assigned his or her own IP address without contacting an administrator.
c) A new device has been put on the LAN without being properly configured.
d) A trunk implemented by assigning multiple IP addresses to a single MAC will also generate this event under normal operation.