禁止匿名用户上传。
Uncomment this if you want the anonymous FTP user to be able to create
new directories.
anon_mkdir_write_enable=YES
anon_mkdir_write_enable=NO
禁止匿名用户建立目录。
Activate directory messages - messages given to remote users when they
go into a certain directory.
dirmessage_enable=YES
设定开启目录标语功能。
Activate logging of uploads/downloads.
xferlog_enable=YES
设定开启日志记录功能。
Make sure PORT transfer connections originate from port 20 (ftp-data).
connect_from_port_20=YES
设定端口20进行数据连接。
If you want, you can arrange for uploaded anonymous files to be owned by
a different user. Note! Using "root" for uploaded files is not
recommended!
chown_uploads=YES
chown_uploads=NO
设定禁止上传文件更改宿主。
chown_username=whoever
You may override where the log file goes if you like. The default is shown
below.
xferlog_file=/var/log/vsftpd.log
设定CentOS Vsftpd配置的服务日志保存路径。注意，该文件默认不存在。必须要手动touch出来，并且由于这里更改了CentOS Vsftpd配置的服务宿主用户为手动建立的Vsftpd。必须注意给与该用户对日志的写入权限，否则服务将启动失败。
If you want, you can have your log file in standard ftpd xferlog format
xferlog_std_format=YES
设定日志使用标准的记录格式。
You may change the default value for timing out an idle session.
idle_session_timeout=600
设定空闲连接超时时间，这里使用默认。将具体数值留给每个具体用户具体指定，当然如果不指定的话，还是使用这里的默认值600，单位秒。
You may change the default value for timing out a data connection.
data_connection_timeout=120
设定单次最大连续传输时间，这里使用默认。将具体数值留给每个具体用户具体指定，当然如果不指定的话，还是使用这里的默认值120，单位秒。
It is recommended that you define on your system a unique user which the
ftp server can use as a totally isolated and unprivileged user.
nopriv_user=ftpsecure
nopriv_user=vsftpd
设定支撑CentOS Vsftpd服务的宿主用户为手动建立的Vsftpd用户。注意，一旦做出更改宿主用户后，必须注意一起与该服务相关的读写文件的读写赋权问题。比如日志文件就必须给与该用户写入权限等。
Enable this and the server will recognise asynchronous ABOR requests. Not
recommended for security (the code is non-trivial). Not enabling it,
however, may confuse older FTP clients.
async_abor_enable=YES
设定支持异步传输功能。
By default the server will pretend to allow ASCII mode but in fact ignore
the request. Turn on the below options to have the server actually do ASCII
