Please refer to our QuickStart guide for setting up SSL/TLS:
You can run the standard wizard to configure a standard server. Once the server has been created, go to the FTPS/SSL tab for the server and enable SSL/TLS. You'll need to create a certificate for use by the server. Click the Certificate Management button, then click Create to generate a new certificate.
Once this has been completed, you'll need to open port 21 for standard FTP and Explicit FTP (AUTH SSL/TLS) and port 990 for Implicit SSL/TLS.
Also, you should enable the PASV mode feature for the server and open a port range on your DSL router or cable modem. Under your server, go to the Connections node. On the Connections Advanced tab you will see a check box that reads "Allow PASV mode connections". Make sure this box is checked.
For more information on configuring Cornerstone MFT for use with a DSL router or cable modem please see our quick start guide: