Discovering SMTP Server and Port by email address

Hello folks,

I`d like to build asp.net web application where anyone could insert its email like [email protected]. As soon as web application receive this input the source code should show me some information such as SMTP IP and PORT from that email address. 

I've searched at internet and got C# DNS examples but it didn't help me at all. I'm probably going to wrong way.

So, if someone could help me doing some highlights I`ll appreciate.

Thanks so far.