解决Debian下启动MySQL报61 Connection refused

1.问题说明

Debian-9.12.1-AMDx64
使用sudo apt-get install mariadb-server mariadb-client在线非编译安装方式
简述：该问题出现一般是没有开放账号权限给外 IP 访问

2.解决思路

在伺服器键入设置mysql_secure_installation重设规则，前提是确认好是否安装到位 MySQLdpkg -l | grep mysql，重设规则这里跳过不需设置 root 密码。

NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!
In order to log into MariaDB to secure it, we'll need the current
password for the root user.  If you've just installed MariaDB, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.
Enter current password for root (enter for none):
OK, successfully used password, moving on...
Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.
You already have a root password set, so you can safely answer 'n'.
Change the root password? [Y/n] n
 ... skipping.
By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] y
 ... Success!
Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] n
 ... skipping.
By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] y
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!
Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] y
 ... Success!
Cleaning up...
All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.
Thanks for using MariaDB!

重启服务systemctl restart mariadb观察是否正常。

若不正常继续键入netstat -tap | grep mysql确认 MySQL 是否在 listen 状态
正常继续键入mysql -u root -p在本地登陆 MySQL，若忘记密码可以去sudo cat /etc/mysql/debian.cnf查看，以下完成设置远程访问的权限

use mysql;
select user,Host from user;
update user set Host='%' where user='root';
grant all privileges on *.* to 'root'@'%' identified by '密码' with grant option;
flush privileges;
exit;

重启服务，观察是否正常。

若还是不正常，继续键入cd /etc/mysql/mysql.conf.d查看配置文件是不是正常对外 IP 访问vim 50-server.cnf

发现 bind-address 配置项错误，理应改成 0.0.0.0
保存后，重启服务，再观察是否正常。