1. Launch the Server Manager. From the Search charm, type in Server Manager to find it.
  2. From the Dashboard, Add Roles and Features. The Add Roles and Features Wizard will begin. Click Next on the first screen.
  3. Select Role-based or feature-based installation.
  4. Select the Essentials Server (which should be highlighted by default).
  5. Click Next to bypass the Roles selections.
  6. Scroll down the list and tick the SMTP Server feature.
  7. A new window will pop up to inform you that some other services will also be installed. Click Add Features to confirm and continue. Click Next to continue past the features selection screen.
  8. Click Install to complete the Installation.
  9. Click Close when the installation has completed.

Configure the SMTP Service

  1. From the Search charm, type IIS. Hover your mouse over one of the selections, and run the Internet Information Services (IIS) 6.0 Manager.
  2. Click Yes to the UAC Prompt. 
  4. Expand to SMTP Virtual Server #1, right click and select Properties.
  5. General Tab: Set the IP Address to the server’s IP address. Note: You can also enable logging is required.
  6. Access Tab: Set the IP for the internal devices in the connection button.

    Add the same IP to the Relay list.
  7. Delivery Tab: Set an external domain – you can use the free customized domain from Microsoft, and you can also optionally add a Smart host, if required. Tick the Attempt direct delivery box, if you want the server to attempt to deliver the email directly first before trying the Smart host.
  8. From the Search charm, type Firewall to locate and run the Windows Firewall with Advanced Security console.
  9. Add a new Inbound Rule. (Right Click on Inbound Rule, and select New Rule)
  10. Select Port.
  11. Type in 25 as the local port.
  12. Click Next (Allow the Connection).
  13. Uncheck Public. (Prevents external access to the server)
  14. Give the rule a name, and click Finish to create the rule.
  15. You should now see a new rule enabled in the firewall management console.
  16. Restart the SMTP Service and set the service for Automatic Start. Open up the Services Management Console. Double Click on the Simple Mail Transfer Protocol service. Stop and then Start the service. Set the Startup type to Automatic.