[root@hyc ~]# ftp 192.168.254.5
Connected to 192.168.254.5 (192.168.254.5).
220 Welcome to blah FTP service.
Name (192.168.254.5:root): user2
331 Please specify the password.
Password:
500 OOPS: bad bool value in config file for: anon_world_readable_only
Login failed.
421 Service not available, remote server has closed connection
在利用虚拟用户登录时出现这种错误，是因为用户配置文件中行末尾有空格。
anon_world_readable_only=NO
anon_upload_enable=YES
anon_mkdir_write_enable=YES
anon_other_write_enable=YES
每行末尾都不能有空格。