Setting up the RPi as an FTP server—over which you and you alone have full control—is quite a simple task. First, install the ProFTP software through:
sudo apt-get install proftpd
Configure it to be “standalone”. Second, edit the config file of the program as follows:
sudo nano /etc/proftpd/proftpd.conf
Add the following parameters:
DefaultRoot ~ AuthOrder mod_auth_file.c mod_auth_unix.c AuthUserFile /etc/proftpd/ftpd.passwd AuthPAM off RequireValidShell off
Restart the service by:
sudo /etc/init.d/proftpd restart
Third, generate a new user as follows:
sudo adduser ftp --home /home/ftp --shell /bin/bash
Change ftp and /home/ftp to a user name and directory of your liking. Choose a password for the new user.
Using a FTP client, you can now connect to your RPi and, for example, store files on it. You can also ssh connect to the RPi using the new user credentials.
Generally SD cards hosting the OS of the RPi and serving as file/data storage are of course not that large. But investing e.g. 50 EUR for a 500 GB external USB drive and connecting such a drive to the RPi is a simple way of using the RPi as a serious ftp server.