How to send message to specific client via client ip address.

What have you tried? Where is some code sample so we can see where you are stuck and help you.

If you haven't tried anything you need to take this question and do a google search. Posting messages in a chat like manner is very common and would yield pages of useful results as a great place to start. Otherwise you are either asking us to teach you how to code, or asking someone to do the work for you, eitherway that is beyond the scope of this forum.

I would suggest you try a bit harder to accomplish what you are wanting to do, then come back here with a clear explanation of your issue, layout what you've tried/gone about attempting, and relevant code samples of your issue and I'm sure you will get more meaningful assistance.