All right, I have a host (of course not my computer) and I've made and share a subdomain(led to a sub directory) for someone for hosting part of my host, set up a FTP account for them to access that subdomain, familiar person so I do not restrict so much, just want to make sure they won't upload some illegal file types like exe or mp3, so I want to restrict their account won't be able to upload some file types like I explain above. My host has Cpanel and I can access WHM of the server if I want. How can I do that?