Hi,
Actually, no, there are no guidelines and we have never had any. If the customer uses Windows servers I think most of them would enable FTP in the IIS. Under Linux/Unix there are often several options to choose from. On Windows, you can also download and install the free FileZilla FTP Server, which seems to be popular.
When it comes to OS resources I would search for the requirements set by the particular FTP server that they use, once they picked one.
In general, I think an FTP server does not need to be very powerful at all when it comes to memory and CPU. Disk space is, of course, the most important property. And network performance.
Perhaps we will get some suggestions from customers already using FTP here?
/Mathias
Thank you Mathias, this is useful.