我有一个应用程序，它要求我的用户通过“远程访问”从任何IP地址（来自他们自己的internet网络的IP地址）连接到在线MySQL数据库，以便它在访问软件之前确认他们在数据库中。

我曾尝试在我的Linux终端中运行命令行，以允许所有用户使用以下命令从任何ip地址进行远程连接:

GRANT ALL ON database_name.* TO root@'%' IDENTIFIED BY 'user_password';

我已经将我的MySQL数据库服务器配置文件配置为启用正确的远程连接（我相信）。

我位于/etc/mysql/mysql.conf.d/mysqld.cnf中的“MySQL数据库服务器配置文件”如下所示:

#
    # The MySQL database server configuration file.
    #
    # You can copy this to one of:
    # - "/etc/mysql/my.cnf" to set global options,
    # - "~/.my.cnf" to set user-specific options.
    # 
    # One can use all long options that the program supports.
    # Run program with --help to get a list of available options and with
    # --print-defaults to see which it would actually understand and use.
    #
    # For explanations see
    # http://dev.mysql.com/doc/mysql/en/server-system-variables.html

    # This will be passed to all mysql clients
    # It has been reported that passwords should be enclosed with ticks/quotes
    # escpecially if they contain "#" chars...
    # Remember to edit /etc/mysql/debian.cnf when changing the socket location.

    # Here is entries for some specific programs
    # The following values assume you have at least 32M ram

    [mysqld_safe]
    socket      = /var/run/mysqld/mysqld.sock
    nice        = 0

    [mysqld]
    #
    # * Basic Settings
    #
    user        = mysql
    pid-file    = /var/run/mysqld/mysqld.pid
    socket      = /var/run/mysqld/mysqld.sock
    port        = 3306
    basedir     = /usr
    datadir     = /var/lib/mysql
    tmpdir      = /tmp
    lc-messages-dir = /usr/share/mysql
    skip-external-locking
    #
    # Instead of skip-networking the default is now to listen only on
    # localhost which is more compatible and is not less secure.
    bind-address        = 0.0.0.0
    #require_secure_transport = on
    #
    # * Fine Tuning
    #
    key_buffer_size     = 16M
    max_allowed_packet  = 16M
    thread_stack        = 192K
    thread_cache_size       = 8
    # This replaces the startup script and checks MyISAM tables if needed
    # the first time they are touched
    myisam-recover-options  = BACKUP
    #max_connections        = 100
    #table_open_cache       = 64
    #thread_concurrency     = 10
    #
    # * Query Cache Configuration
    #
    query_cache_limit   = 1M
    query_cache_size        = 16M
    #
    # * Logging and Replication
    #
    # Both location gets rotated by the cronjob.
    # Be aware that this log type is a performance killer.
    # As of 5.1 you can enable the log at runtime!
    #general_log_file        = /var/log/mysql/mysql.log
    #general_log             = 1
    #
    # Error log - should be very few entries.
    #
    log_error = /var/log/mysql/error.log
    #
    # Here you can see queries with especially long duration
    #slow_query_log     = 1
    #slow_query_log_file    = /var/log/mysql/mysql-slow.log
    #long_query_time = 2
    #log-queries-not-using-indexes
    #
    # The following can be used as easy to replay backup logs or for replication.
    # note: if you are setting up a replication slave, see README.Debian about
    #       other settings you may need to change.
    #server-id      = 1
    #log_bin            = /var/log/mysql/mysql-bin.log
    expire_logs_days    = 10
    max_binlog_size   = 100M
    #binlog_do_db       = include_database_name
    #binlog_ignore_db   = include_database_name
    #
    # * InnoDB
    #
    # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
    # Read the manual for more InnoDB related options. There are many!
    #
    # * Security Features
    #
    # Read the manual, too, if you want chroot!
    # chroot = /var/lib/mysql/
    #
    # For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
    #
    # ssl-ca=/etc/mysql/cacert.pem
    # ssl-cert=/etc/mysql/server-cert.pem
    # ssl-key=/etc/mysql/server-key.pem

我还尝试使用以下命令行解除防火墙阻塞以启用tcp连接:

sudo ufw allow 3306/tcp

我的桌面应用程序中的连接字符串如下所示:

MysqlConn.ConnectionString = "server=MyServerIPaddress;Port=3306;database=MyDatabaseName;Uid=root;Pwd=MyPassword;Connect Timeout=30;SslMode=none;"

我的用户仍然得到“无法连接到任何指定的mysql主机”。 错误消息。 欢迎任何支持。