Accesso a MySql locale da remoto

1. set up user with wildcard:
   create user 'root'@'%' identified by 'some_characters';
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'
IDENTIFIED BY PASSWORD 'some_characters'
WITH GRANT OPTION
2. vim /etc/my.cnf
   add the following:
   bind-address=0.0.0.0

restart server, you should not have any problem connecting to it.