I am going to ask what some might think as a silly question.
When you think of any client - Browser, FTP, VPN, you automatically think/know that it must connect to a server.
I am running a CentOS VPS and I want to upload files to it. Now I have an ftp client on my Windows PC or I can just use the browser to upload files.
My questionn: Why do I need an FTP server on my VPS like VSFTPD? Why can Apache just listen to port 21 and manage file transfer itself (like downloading a file over port 80)? Why does it have to happen between ftp client and ftp server?