关于连接 VirtualBox NAT 下的 MySQL 服务

这两天尝试外部连接 VirtualBox 中 CentOS 的 MySQL 服务器，可谓历尽一番辛苦。

最开始用的是 Java 的 mysql 驱动连接，无奈连接不上。然后下载 SQLyog 的 Community 版进行连接，依然难以通过。

于是开始此次的辛苦旅程。

1 首先想到的 MySQL 服务本身设置的问题。

问题何在呢，端口 or IP？检查尝试设置之后，无论是port forwarding 还是 bind-address，问题依旧。

之后尝试修改MySQL的用户访问控制。

GRANT ALL ON *.* TO root@'%' IDENTIFIED BY 'root';

继续测试：

mysql:
[echo] running
[java] ......
[java] Error
[java] com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
[java]
[java] ** BEGIN NESTED EXCEPTION **
[java]
[java] com.mysql.jdbc.CommunicationsException
[java] MESSAGE: Communications link failure due to underlying exception:
[java]
[java] ** BEGIN NESTED EXCEPTION **
[java]
[java] java.io.EOFException
[java]
[java] STACKTRACE:
[java]
[java] java.io.EOFException
[java]     at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1963)
[java]     at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:557)
[java]     at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1027)
[java]     at com.mysql.jdbc.Connection.createNewIO(Connection.java:2743)
[java]     at com.mysql.jdbc.Connection.<init>(Connection.java:1553)
[java]     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
[java]     at java.sql.DriverManager.getConnection(DriverManager.java:620)
[java]     at java.sql.DriverManager.getConnection(DriverManager.java:200)
[java]     at org.huys.db.MySQLConnect.main(Unknown Source)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
[java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[java]     at java.lang.reflect.Method.invoke(Method.java:616)
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.run(ExecuteJava.java:217)
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:152)
[java]     at org.apache.tools.ant.taskdefs.Java.run(Java.java:764)
[java]     at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:218)
[java]     at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:132)
[java]     at org.apache.tools.ant.taskdefs.Java.execute(Java.java:105)
[java]     at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
[java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[java]     at java.lang.reflect.Method.invoke(Method.java:616)
[java]     at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
[java]     at org.apache.tools.ant.Task.perform(Task.java:348)
[java]     at org.apache.tools.ant.Target.execute(Target.java:357)
[java]     at org.apache.tools.ant.Target.performTasks(Target.java:385)
[java]     at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
[java]     at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
[java]     at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
[java]     at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
[java]     at org.apache.tools.ant.Main.runBuild(Main.java:758)
[java]     at org.apache.tools.ant.Main.startAnt(Main.java:217)
[java]     at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
[java]     at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)
[java]
[java]
[java] ** END NESTED EXCEPTION **
[java]
[java]
[java]
[java] Last packet sent to the server was 33 ms ago.
[java]
[java] STACKTRACE:
[java]
[java] com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
[java]
[java] ** BEGIN NESTED EXCEPTION **
[java]
[java] java.io.EOFException
[java]
[java] STACKTRACE:
[java]
[java] java.io.EOFException
[java]     at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1963)
[java]     at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:557)
[java]     at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1027)
[java]     at com.mysql.jdbc.Connection.createNewIO(Connection.java:2743)
[java]     at com.mysql.jdbc.Connection.<init>(Connection.java:1553)
[java]     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
[java]     at java.sql.DriverManager.getConnection(DriverManager.java:620)
[java]     at java.sql.DriverManager.getConnection(DriverManager.java:200)
[java]     at org.huys.db.MySQLConnect.main(Unknown Source)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
[java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[java]     at java.lang.reflect.Method.invoke(Method.java:616)
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.run(ExecuteJava.java:217)
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:152)
[java]     at org.apache.tools.ant.taskdefs.Java.run(Java.java:764)
[java]     at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:218)
[java]     at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:132)
[java]     at org.apache.tools.ant.taskdefs.Java.execute(Java.java:105)
[java]     at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
[java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[java]     at java.lang.reflect.Method.invoke(Method.java:616)
[java]     at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
[java]     at org.apache.tools.ant.Task.perform(Task.java:348)
[java]     at org.apache.tools.ant.Target.execute(Target.java:357)
[java]     at org.apache.tools.ant.Target.performTasks(Target.java:385)
[java]     at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
[java]     at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
[java]     at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
[java]     at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
[java]     at org.apache.tools.ant.Main.runBuild(Main.java:758)
[java]     at org.apache.tools.ant.Main.startAnt(Main.java:217)
[java]     at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
[java]     at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)
[java]
[java]
[java] ** END NESTED EXCEPTION **
[java]
[java]
[java]
[java] Last packet sent to the server was 33 ms ago.
[java]     at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:625)
[java]     at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1027)
[java]     at com.mysql.jdbc.Connection.createNewIO(Connection.java:2743)
[java]     at com.mysql.jdbc.Connection.<init>(Connection.java:1553)
[java]     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
[java]     at java.sql.DriverManager.getConnection(DriverManager.java:620)
[java]     at java.sql.DriverManager.getConnection(DriverManager.java:200)
[java]     at org.huys.db.MySQLConnect.main(Unknown Source)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
[java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[java]     at java.lang.reflect.Method.invoke(Method.java:616)
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.run(ExecuteJava.java:217)
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:152)
[java]     at org.apache.tools.ant.taskdefs.Java.run(Java.java:764)
[java]     at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:218)
[java]     at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:132)
[java]     at org.apache.tools.ant.taskdefs.Java.execute(Java.java:105)
[java]     at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
[java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[java]     at java.lang.reflect.Method.invoke(Method.java:616)
[java]     at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
[java]     at org.apache.tools.ant.Task.perform(Task.java:348)
[java]     at org.apache.tools.ant.Target.execute(Target.java:357)
[java]     at org.apache.tools.ant.Target.performTasks(Target.java:385)
[java]     at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
[java]     at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
[java]     at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
[java]     at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
[java]     at org.apache.tools.ant.Main.runBuild(Main.java:758)
[java]     at org.apache.tools.ant.Main.startAnt(Main.java:217)
[java]     at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
[java]     at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)
[java]
[java]
[java] ** END NESTED EXCEPTION **
[java]
[java]
[java]
[java] Last packet sent to the server was 1 ms ago.
[java]     at com.mysql.jdbc.Connection.createNewIO(Connection.java:2814)
[java]     at com.mysql.jdbc.Connection.<init>(Connection.java:1553)
[java]     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
[java]     at java.sql.DriverManager.getConnection(DriverManager.java:620)
[java]     at java.sql.DriverManager.getConnection(DriverManager.java:200)
[java]     at org.huys.db.MySQLConnect.main(Unknown Source)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
[java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[java]     at java.lang.reflect.Method.invoke(Method.java:616)
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.run(ExecuteJava.java:217)
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:152)
[java]     at org.apache.tools.ant.taskdefs.Java.run(Java.java:764)
[java]     at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:218)
[java]     at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:132)
[java]     at org.apache.tools.ant.taskdefs.Java.execute(Java.java:105)
[java]     at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
[java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[java]     at java.lang.reflect.Method.invoke(Method.java:616)
[java]     at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
[java]     at org.apache.tools.ant.Task.perform(Task.java:348)
[java]     at org.apache.tools.ant.Target.execute(Target.java:357)
[java]     at org.apache.tools.ant.Target.performTasks(Target.java:385)
[java]     at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
[java]     at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
[java]     at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
[java]     at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
[java]     at org.apache.tools.ant.Main.runBuild(Main.java:758)
[java]     at org.apache.tools.ant.Main.startAnt(Main.java:217)
[java]     at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
[java]     at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)

2 防火墙

先检查 Host 上的防火墙，关闭之后测试结果：问题依旧。

检查 CentOS 的 iptables 设置。

iptables -I RH-Firewall-1-INPUT 11 -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT

测试一下：

mysql:
[echo] running
[java] ......
[java] Connection Successful!

历尽艰辛，终于见到曙光了。

进一步修改下 MySQL 的用户访问控制，仅允许 guest 所在的 IP地址段访问。因为 IP Forwarding 的设置，已经可以通过外部地址访问 VirtualBox 中的 MySQL 服务了。

GRANT ALL ON *.* TO root@'10.0.2.%' IDENTIFIED BY 'root';