ABSTRACT
Advanced FTP servers such as wu-ftpd provide extensive controls for controlling FTP access to the target system. This access does not extend to the IP layer, as the typical FTP client does not offer encryption of the data stream. A further requirement is to protect the data once stored on the remote system to limit the possibility of unauthorized access, retrieval, and modification of the data. However, using /etc/f tpusers prevents access to the FTP server and eliminates the problem of unauthorized data movement to or from the FTP server. Most current FTP server implementations offer the /etc/ftpusers feature. The real keyword matches users to their real user accounts. Anonymous matches users who are using anonymous FTP access, while guest matches guest account access. Preventing anonymous access to the FTP server is best accomplished by removing the ftp user from the /etc/passwd file. This instructs the FTP server to deny all anonymous connection requests.
