The ftpd security file rejects remote logins to local user accounts specified in /etc/ftpusers. Restricted accounts appear one to a line; white space is prohibited. Account names must match exactly the user account name in the /etc/passwd file. If the file does not exist, ftpd does not do security checks.
The following are sample entries in an /etc/ftpusers file: root guest ftp user1 UUCP
Daemons: ftpd(8) delim off