ok, lets say I havn't installed proftpd or anything, i just have REGULAR ftp enabled on my box. How can I disable anonymous logins?

I am currently using Debian 4, and I assume that I could edit the /etc/ftpusers file, BUT I just read in the man page for it that proftpd uses it. So what file do I edit if I am not using proftpd or anything other than regular ftp?