Setting up SMTP server for email relay

Updated by Bryan Jones


This document will cover how to set up a SMTP relay that will allow programs that do not support webmail systems like Gmail, Yahoo, Hotmail, etc.


Install SMTP Server in Windows Server as a feature using the Add Roles and Features. This will differ from one OS to another but is likely available on all Windows Server platforms and some Windows Desktop platforms.

Configure the server

  1. From the Run menu
  2. Enter inetmgr6 in the dialog box then click OK to load IIS Manager 6. 
  3. In IIS 6 Manager right-click on SMTP Server and select Properties.
  4. On the Access tab, click on Relay....
  1. Click the ADD button and set a relay for
This would allow local relay from software running on this computer only. If this is being used for other devices it is best to list them individually, by IP Address so you do not create an open relay server.
  1. Add additional devices by specifying the IP address of the device (or a Range of devices). For example, a remote control with an IP address of could be allowed to send by granting it explicit permission by adding it to the list.
  1. Click OK on any setup dialogs when complete so the changes are applied properly.

Configure the sender

Since we have allowed SMTP direct sending your clients (the sender) will require no authentication. We have specifically allowed them by IP address. Here are a couple of examples.

Pathfinder PC
25-Seven PDM

For the PDM we have specified the mail server address of the computer where we set up the SMTP Server role.


This is offered to you without warranty or support of any kind with the hope that you will find this useful. It was written with information gathered from, and a nod to,

There are many other "free" SMTP mail server programs that could be used as well. This is simply one example.

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