这可能意味着你的 MySQL 服务器只监听 localhost 接口.

如果你有这样的行:

绑定地址 = 127.0.0.1

在您的my.cnf 配置文件中，您应该对它们进行注释(在行首添加#)，然后重启MySQL.

sudo service mysql restart

当然，要做到这一点，您必须是服务器的管理员.

I installed mysql server on linux box IP = 192.168.1.100 but when i try to connect to this IP it alway error(111). but use localhost and 127.0.0.1 is OK.

beer@beer-laptop# ifconfig | grep "inet addr"
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0

beer@beer-laptop# mysql -ubeer -pbeer -h192.168.1.100
ERROR 2003 (HY000): Can't connect to MySQL server on '192.168.1.100' (111)

beer@beer-laptop# mysql -ubeer -pbeer -hlocalhost
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 160
Server version: 5.1.31-1ubuntu2 (Ubuntu)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> 

beer@beer-laptop# mysql -ubeer -pbeer -h127.0.0.1
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 161
Server version: 5.1.31-1ubuntu2 (Ubuntu)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> 

Connect from another machine it also error 111.

another@another-laptop# mysql -ubeer -pbeer -h192.168.1.100
ERROR 2003 (HY000): Can't connect to MySQL server on '192.168.1.100' (111)

How difference between use localhost/127.0.0.1 and 192.168.1.100 in this case. I don't know how to connect to this database from another machine.

Help please. Thank.

It probably means that your MySQL server is only listening the localhost interface.

If you have lines like this :

bind-address = 127.0.0.1

In your my.cnf configuration file, you should comment them (add a # at the beginning of the lines), and restart MySQL.

sudo service mysql restart

Of course, to do this, you must be the administrator of the server.