Q: 當在另一台機器上登錄MySQL時出現如下錯誤：
ERROR 2003 (HY000): Can't connect to MySQL server on 'x.x.x.x' (111)
A: 原因是MySQL考慮到安全因素，默認配置只讓從本地登錄
打開 /etc/mysql/my.cnf 文件，找到 bind-address = 127.0.0.1 修改為 bind-address = 0.0.0.0
重啟mysql : sudo /etc/init.d/mysql restart
可參考：
> I've already check my /etc/my.cnf file for a "binding"
> line. Its not
> there. I also found an item online that indicated
> adding:
>
Look for the option "skip-networking". This disables TCP/IP so the
server only accepts local connections via the Unix socket. This sounds
like your situation.
Note that a "could not connect" error means just that. If the problem
was related to user privileges you would get an "access denied" error.
Q: 還一種情況出現類似下面的錯誤：
ERROR 1045 (28000): Access denied for user 'test'@'x.x.x.x' (using password: NO)
A: 原因是沒有給登錄用戶名設置遠程主機登錄的權限。
在本地用 root 登錄: mysql -u root -p
修改 MySQL 數據庫中 user 表中 對應用戶名的 Host 字段，將 localhost 改為 %
use mysql;
update user set Host = '%' where User = 'username';
