E-MailRelay

What is it?

E-MailRelay is a simple store-and-forward message transfer agent and proxy server. It runs on Unix-like operating systems (including Linux), and on Windows.

When used as proxy server the E-MailRelay program (emailrelay) runs in the background and accepts e-mail from local e-mail client programs (KMail, Outlook etc.) or from the outside world, using the SMTP protocol. As soon as an e-mail message is received it is forwarded on to the next SMTP server for onward delivery. This becomes more useful when you add in your own message processing: as each message is received it can be passed one of your programs for editing, filtering, encrypting etc.

Get it here EmailRelay

Or my local copy Version 1.9 EmailRelay

 

Configure Windows Server 2012 SMTP Relay

Go in Server Manager to Tools > Internet Information Services (IIS) 6.0 Manager > Right-click [SMTP Virtual Server #1] > Click ”Properties” .

Click ”Access” tab > Click Connection > Check ”All except the list below” > OK > Click Relay > Check ”All except the list below” > OK.

Click ”Delivery” tab > Click ”Outbound Security” > Check ”Basic Authentication” > Type username and password of Office 365 user > Click ”TLS encryption” > OK >
Click ”Outbound connections” > Change ”TCP port” to 587 > OK > Click ”Advanced” > Fill in ”Smart host” with the name of the Office 365 SMTP server > OK > OK.

Check firewall rules – ”Simple Mail Transfer Protocoll (SMTP-In)”

Warning! You have an open relay now. Use this setup to check the email notification system. When you see it´s fully functional go back to the ”Access” tab and narrow down the ”Connection” and ”Relay” settings to the necessary systems. When no other system needs to relay, just check ”Only the list below” and grant ”127.0.0.1ÔÇ│ access.