Examine this output: $ ftp o16.example.com Connected to o16.example.com
(192.168.40.131) 220 (vsFTpd 2.2.2) Name (o16.example.com:oracle): A carriage return is
now entered on the keyboard and the result is shown: $ 30 permission denied. Login failed.
ftp> Why is the oracle user denied access to the FTP server on the 016.example.com host?
A.
The Oracle user is listed in /etc/vsftpd/ftpusers.
B.
The oracle user is listed in /etc/vsftpd/user_list and the USERLIST_ENABLE setting is
set to YES in /etc/vsftpd/vsftpd.conf.
C.
The Oracle user is listed in /etc/vsftpd/user_list and USERLIST_ENABLE setting is set to
NO in /etc/vsftpd/vsftpd.conf.
D.
The LOCAL_ENABLE setting is set to NO in /etc/vsftpd/vsftpd.conf.
E.
The Oracle user does not exist on the o16.example.com host.
B
Reference:
https://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-ftp-vsftpd-conf.html
See userlist_enable section
Answer C, Reference:
https://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-ftp-vsftpd-conf.html
See userlist_enable section
userlist_enable directive and set to NO, all local users are denied access unless the username is listed in the file specified by the userlist_file directive. Because access is denied before the client is asked for a password, setting this directive to NO prevents local users from submitting unencrypted passwords over the network.
The default value is YES.