Steps to install and configure FTPS (FTP over SSL) on Windows 2012 R2 Server
1. Install IIS from Server Manager
2. Select both “FTP Service” and “FTP Extensibility” during the installation.
3. Once IIS is installed, open IIS Manager then double-click “Server Certificates”, then import your SSL certificate.
Make sure that “Allow this certificate to be exported” option is ticked when importing.
4. Add FTP Site
5. Specify the path
6. Select “Require SSL” and your SSL certificate
7. Select “Basic”, “Specified users” and specify the account to allow access, then set the permissions
8. Click the server in the tree and double-click “FTP Firewall Support”
9. Specify the data channel port range for PASV mode
10. Click the FTP site in the tree and double-click “FTP Firewall Support”
11. Type the external IP address of your firewall.
12. Make sure that those ports are allowed in Windows Firewall.
13. Also make sure that your firewall allows those ports.
14. Restart the server just in case as I sometimes see that the server is not accessible until the server is restarted.