关于vsftp的日志格式中有些字段描述不理解

austin22

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     filename            The canonicalized (all symbolic links are resolved) abso-
                    lute pathname of the transferred file.

                    In case of the chrooted FTP session this field can be
                    interpreted as the pathname in the chrooted environment
                    (the default interpretation) or as the one in the real
                    file system. The second type of interpretation can be
                    enabled by the command-line options of the ftpd(.

     authentication-method
                    The used method of the authentication. The set of possible
                    values is:

                    0         None.

                    1         RFC931 Authentication (not in use).

     authenticated-user-id
                    The user id returned by the authentication method. The `*'
                    symbol is used if an authenticated user id is not avail-
                    able.
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这2段E文我不太明白意思，有人能说明一下吗？
首先说明下我的理解：
filename：理解成绝对路径名，实际情况是ftp用户看到的路径；
authentication-method:实际情况不管用什么账户，都显示0；
authenticated-user-id：不理解，实际情况是我用系统账户登录。

vsftp格式引用
http://bsdftpd-ssl.sc.ru/doc/unix/xferlog.5.txt