現象

報錯：ERROR 1130: Host '172.21.200.35' is not allowed to connect to this MySQL server

方法一：修改 user 表 host 字段（改表法）

mysql -u root -p
mysql> USE mysql;
mysql> UPDATE user SET Host = '%' WHERE User = 'root';
mysql> SELECT Host, User FROM user;

% 表示允許任意主機連接。

方法二：GRANT 授權語句（推薦）

允許任意主機

GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'password' WITH GRANT OPTION;

允許特定 IP

GRANT ALL PRIVILEGES ON *.* TO 'root'@'172.21.200.35' IDENTIFIED BY 'password' WITH GRANT OPTION;

執行後 FLUSH PRIVILEGES; 刷新生效。方法二更安全、靈活，不直接操作系統表。