So is setting up an ftp user really just setting up a user in ubuntu? I saw something about setting up a user without a home directory. What other things are important? I'd like to give the user the least amount of privilege possible. They only need access to /var/www/example.com and everything beneath it. So I'd like when they log in to ftp that they can only see that (not see any other folders/files). I'm using vsftpd if that matters.
Well, if you are really concerned about security, then I would recommend not to use FTP at all and go with SCP (WinSCP is an excellent Windows client for that, and FileZilla also supports it). For that to work, all you need to do is add the new user, and point his/her home directory to /var/www/example.com/
Under Ubuntu, if they log in using SSH, you can hardly prevent them from seeing other things, but you can remove their entry in /etc/sudoers (using visudo), which will prevent them from doing anything.
I would further recommend to disable plain password logins and generate keys for all user accounts. There are numerous articles on the Internet on how to do this.
If you really want to use vsftpd, then do this:
This works together with:
In fact, you probably want to have the following options in the config file:
nopriv_user=ftp chroot_list_enable=YES chroot_list_file=/etc/vsftpd/chroot_list passwd_chroot_enable=YES pam_service_name=vsftpd userlist_enable=YES user_config_dir=/etc/vsftpd/user_conf
More info can be found in the man page for vsftpd.