mysql修改登录密码、创建新的登录用户、开启外部访问的端口

use mysql;
delete from user where user='';
flush privileges;

create user 'test'@'%' identified by '123456';

grant all privileges on *.* to 'root'@'%' identified by '123';

set password for 'root'@'%' = password('321');

select user,host,password from user;
update user set password=password('123') where user='root' and host='localhost';

delete from user  where user='test' and host='%';
flush privileges;       #清除缓存，使操作立即生效

whereis iptables
/usr/sbin/iptables  -I INPUT -p tcp --dport 3306 -j ACCEPT