1. Stunnel Introduction

This document will explain the procedures for installing and configuring Stunnel, a third-party SSL tunneling client to be used if your SMTP server requires SSL. Stunnel is required for WIN-911 V7 as it does not natively support SSL. We have provided an example Stunnel configuration in this article that will be using Gmail's SMTP server. While we are using Gmail as an example, please be aware that Google enforces sending limits on Gmail accounts. Currently, the limit is 500 emails in a day. If your WIN-911 configuration contains a large number of Email Contacts and/or Alarms, you will need to find an alternative to Gmail. 

A. Download and Installing Stunnel 

Stunnel 5.40 can be downloaded from the Stunnel website. During the installation process, make sure you enter the proper Organization information. The information creates an SSL certificate. If you skip this step, Stunnel will not function properly. 


B. Configure Stunnel

You can use Stunnel to configure any SSL enabled server. As we mentioned in the Introduction, we have provided an example using Gmail.

Stunnel is configured with a text-based configuration file titled stunnel.conf. You can find the file in the directory Stunnel is installed to.

You can also find it from selecting: Start > All Programs > Stunnel > Edit stunnel.conf.

Once you’ve opened the stunnel.conf file in Notepad you’ll be presented with their default configuration. 

This configuration is not needed, you will need to remove it by highlighting the text and deleting it. Copy the text below into the blank file:

client = yes
accept =
connect = smtp.gmail.com:465

Save the configuration and now you can start the Stunnel runtime. If Stunnel was running then you will need to open the Stunnel GUI and select:

Configuration > Reload stunnel.conf from the menu bar.

The accept property is used to specify the host that will accept the connection and the connect property is used to specify the remote host. If you are using a connection other than Gmail, you should only have to change the SMTP connect server and port.

C. Configuring Stunnel as a Windows Service

Install Stunnel as a service by going to:

Start > All Programs > Stunnel > Service Install. 

A successful dialog should appear. You can now find Stunnel in your Windows Services list. Set the service to start automatically. We suggest rebooting your system and triggering an alarm after you have WIN-911 and Stunnel working to ensure it is functioning properly.

D. Configure Gmail

In order to send email through Gmail using 3rd party email clients, including WIN-911, you must enable the less secure apps feature. You can do this by logging into the Gmail account you'd like to use and open the Less Secure Apps page.

Once you select the proper access option for less secure apps, you can log out.

2. Configure WIN-911

Use the following screenshots to configure WIN-911 to use Stunnel.

Follow these SMTP Settings to set up WIN-911

Follow these Authentication Settings 

Restart WIN-911 and test your settings by sending a Manual Message.

Find additional support information at Stunnel.

Technical Support

To create a support case, you will need either your Maintenance Support number or your CD Tracking number. You can create a Case online or contact the product support line: (512)326-1011.