How do I check for duplicate IP addresses in Linux?

Linux doesn’t do an active monitoring or reporting of duplicate ip, after the interface is initialized. To check for duplicate IP addresses in Linux:

Log into your server via console and from the command line run

arping -D -q -I eth0 -c 2 192.168.1.250 ; echo $?

If the above commands return 0, then no one responded to your arp request and therefore no one else is using your IP address.