Today’s article isn’t about Free Software, it’s something I encountered at work (on a Mac OS X machine). Regardless, I think the solution may be of use to other people.
I ran into the error “530 User may not use FTP” attempting to log into the (default) FTP server on Mac OS X 10.6. Googling, I found that other people had encountered the same issue but no solutions were available.
You’ve enabled FTP (Under “System Preferences” -> “Sharing” -> “File Sharing” section -> “Options” -> “Share files and folders under FTP”). The issue is when attempting to login using an FTP client you get the error “530 User may not use FTP”.
You’re attempting to log in as a user in the “FTP user disallowed” list (I was trying to log in as “administrator”). Edit the file /etc/ftpusers and remove your username from the list, then try again.
Note: FTP traffic is unencrypted. This means that usernames/passwords are sent in plain text and for this reason I recommend using SFTP/SCP whenever possible.