MySQL有关1042 Can’t get hostname for your address的问题分析解决过程

[Comment 1]
 前同事企鹅上面说他安装的mysql 5.5，发现用mysql客户端远程连接的时候，报1042-Can’t get hostname for your address错误，但是权限已经grant了并且grant成功了。
 这个报错的意思是“您的地址无法获得主机名”，我就想到了skip-name-resolve参数。

官方文档:

• --skip-name-resolve

  Use IP addresses rather than host names when creating grant table entries. This option can be useful if your DNS does not work.

• --skip-name-resolve

  Do not resolve host names when checking client connections. Use only IP numbers. If you use this option, all Host column values in the grant tables must be IP numbers or localhost. See Section 7.7.11, “How MySQL Uses DNS”.

  mysql> show variables like '%skip_name_resolve%';
  +-------------------+-------+
  | Variable_name     | Value |
  +-------------------+-------+
  | skip_name_resolve | ON   |
  +-------------------+-------+
  1 row in set (0.00 sec)

  mysql> set global skip_name_resolve=0;
  ERROR 1238 (HY000): Variable 'skip_name_resolve' is a read only variable
  mysql>
  失败了，看来是只有修改my.cnf了

  在[mysqld]节点下修改

  skip-name-resolve
  #忽略主机名的方式访问
  lower_case_table_names=1
  #忽略数据库表名大小写

  重启MySQLD process即可。

  [Comment 2]
  前同事企鹅留言：
  mysql -h 192.168.1.101 -u root -p
  访问不了，我本地的mysql.192.168.1.101是本地ip地址。
  grant all privileges on *.* to 'hive'@'192.168.1.101' identified by 'hive' with grant option;就是报连接不上，权限问题，怎么搞定。

  查看官方文档：

• hostname

  Variable Name	hostname
  Variable Scope	Global
  Dynamic Variable	No
  	Permitted Values
  	Type	string

  The server sets this variable to the server host name at startup.

  mysql> show variables like '%hostname%';
  +---------------+-------------------------------------------+
  | Variable_name | Value                                     |
  +---------------+-------------------------------------------+
  | hostname      | xxxxx.china.online.xx.com |
  +---------------+-------------------------------------------+
  1 row in set (0.00 sec)
  
  mysql> set global hostname='xxxxx2.china.online.xx.com';
  ERROR 1238 (HY000): Variable 'hostname' is a read only variable
  mysql> 

  失败了，只有修改my.cnf了，在mysqld选项下面

  [mysqld]
  # 注释掉参数即可，mysql直接用本机ip不能访问
  # hostname

  然后重启mysqld 服务即可。