FTP Import of PST File
From mail2web.com Wiki
FTP is short for File Transfer Protocol and is used to upload or download files from one computer to another.
Because .pst files for Exchange are often quite large, it becomes difficult to upload them through a web page when they are larger than 50 MB. Therefore if you are uploading a .pst file that is larger than 50 MB to import into your Exchange account, or you have Exported your .pst file from your Exchange account, then you'll need to use FTP to transfer the file.
For Windows users we recommend the FileZilla FTP program. If you are simply downloading your exported .pst file, you could also just use your browser. Simply type the FTP information in the address field in the following format: