Using Stunnel

Stunnel is a free SSL proxy server that provides SSL services to Windows programs. Stunnel is easy to install, very robust, and functions transparently with very little overhead.

Stunnel is required by SEE application programs when connecting to an email server that requires SSL services such as Gmail, Hotmail, and Yahoo.

If you are using SEE version 7.0 (or above), once downloaded & unzipped, Stunnel can be configured and controlled automatically without any user intervention.

Using Stunnel (Auto Configuration)

With the "auto configuration" method of using Stunnel, all that is required is that you download & unzip Stunnel into a local directory.

Step 1: Download Stunnel

Stunnel may be downloaded from
or (version 5.42) from

Step 2: Install Stunnel

After downloading Stunnel from or from our web site, unzip the file ( into your SSL directory. The recommended directory is \SEE4C\SSL (C/C++), \SEE4D\SSL (Delphi), \SEE4VB\SSL (Visual basic), etc.

Next, the Stunnel installation program must be run, which will download the required Stunnel files from as well as create a new stunnel.pem certificate file.

You are now ready to run SEE programs that connect to email servers that require SSL. SEE will configure, load, and unload Stunnel automatically. See the MailSSL and ReadSSL example programs.