[root@hyc ~]# ftp 192.168.254.5

Connected to 192.168.254.5 (192.168.254.5).

 Welcome to blah FTP service.

Name (192.168.254.5:root): user2

 Please specify the password.

Password:

 OOPS: bad bool value in config file for: anon_world_readable_only

Login failed.

 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。