What is a Post Fix, Can some one explain in a very Simple Language.
I have a dedicated server, what is needed to Install on it so that I can Convert it into SMTP, with authentication.
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.
Postfix is an SMTP (Simple Mail Transfer Protocol) server. Look at this page to read more about SMTP protocol.
Your question can not be answered in its current form. You need to read a lot more about this topic and if you have any specific problem, we can help.