Question: Praveen here ,I have registered www.abc.com and i have my web server sitting at our corporate office aand a public ip mapped to it . i am able to access the application from the external network directly typing the ip address , but i want to access this application using the registered dns name ie abc.com fromt the external network, upon typing the abc.com where it should directly go the public ip and open up the application sitting in there.

Can anyone help me in this , how to do it step by step...

Answer: 
You need to use your domain registrar's tools to create DNS A records that point your domain name to your IP address.
Go to your domain registrar's site ---> Under your domain(abc.com), click manage domains----> Now add your A record as 

@ your-ip 

here '@' specifies your domain name.