We a recent customer that wanted to use FTP over SSL on IIS. So below is what we did to get it to work (read We as Me).
Pre-Steps are to install IIS and Create an FTP, Have a SSL Cert and IP Addresses
1. At your IIS top Level Click on the Server Name and Select FTP Firewall Support
2. Enter the Range of Ports for your Data Channel Port Range – Then open these ports Inbound through your firewall
3. Select the FTP Site you created and select FTP SSL Settings
a. Select the SSL Certificate for the site
b. Ours we selected Custom and Set Control Channel for Require only for credentials and Allow for Data Channel
4. Select the FTP Firewall Support for the FTP Site
a. Set your IP address of your firewall in to External IP Address of Firewall
5. Select the FTP Authentication and Enable Basic Authentication (we also disabled Anonymous)
6. Ensure FTP Authorized Roles is Allow for All users Read and Write
Test