[CentOS] Inquiry:How to check for IP conflict on my CentOS server?

Tue Nov 10 11:17:49 UTC 2009
John Doe <jdmls at yahoo.com>

From: hadi motamedi <motamedi24 at gmail.com>
>Please be informed that I have set an secondary IP address on my CentOS 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 ? 

Why not ask the System Administrator if this IP is available?

JD