Set up email on Virtual Private Server (VPS) - Server Admin required

I have a dedicated cloud VPS with UnlimitedWebHosting that is un-managed. I am looking for Linux Server Administrator with security hardening experience to perform/help with the following tasks:
-Help configuring email: Webmail works, but configuring Outlook does not (SMTP error).
-Configure Spam filter
-Security hardening

Server Details:
OS: CentOS
Ram: DediCloud has 3 GB Dedicated RAM, this will burst to 8GB if needed.
CPU: Quad Core Xeon CPU.

All reasonable bids will be considered.

Let me know if you have any questions.