I need to develop a program for uploading files from a Windows server to a AS/400 machine. I need to check the integrity of the file once it has been uploaded to the AS/400, to see it has not changed. I have to give a proposal of what to use in the AS400 side, for example a FTP server, a custom program, a web service, or whatever I think is the best solution. In the windows end I know everything I need but I have no idea what to use or develop in the AS400 side. Any advice will be welcome, I know well how to program in C or java or can have another person to program what is needed. I would use an already done FTP server but not sure if it comes with AS/400 nor how to install it. As you can guess I almost know nothing about AS/400.