Inquiry:How to check for IP conflict on my Debian server?

[hadi motamedi]

 Dear All
Please be informed that I have set an secondary IP address on my Debian
server to be able to reach to another Intranet , as the followings:
#ifconfig eth0:1 172.18.209.1 netmask 255.255.0.0 up
But I am not aware if any other node on the new Intranet is making use of
this IP address . Can you please do me favor and let me know how can I check
if any IP conflict occured ?
Let me thank you in advance