If you're looking for a highly professional, no nonsense FTP server then you can't do much better than FTP Serv-U.
In this latest release, the developers have completely re-engineered Serv-U FTP Server from the ground up to be faster, more secure, and more flexible. Particularly for those seeking a highly secure FTP server, this is a rock solid product that will give you peace of mind. Serv-U supports high-grade 128-bit Secure Socket Layer (SSL) encrypted communications using FTPS and HTTPS. When using FTPS or HTTPS, file transfers and remote administration sessions are secured meaning that no one can see, interrupt or access in anyway the transfers you may be making. However, this is a pretty standard feature for FTP clients but what's great about FTP Serv-U is that you can completely restrict access to the entire File Server, specific domains, or even individual user accounts with powerful IP access rules. You can even specify a domain name that allows dynamic DNS to grant access for mobile users - great for if you need to administer your files on the move from your mobile device.
Highly secure and rich with features, this is one FTP server that no professional administrator should ignore.