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Not able to connect to MariaDB hosted on Raspberry Pi – Phpmyadmin

I’m coding a little project in java, in which I want to compare the inserted password with stored sql input.

Everything is hosted on my Raspberry Pi 3:

  • Apache 2.4.37
  • Php 7.4.5
  • MariaDB 10.0
  • phpMyAdmin 5.0.2

The pc i’m conding on and the raspberry are in the same network.
I can access the database easily with phpMyAdmin, but not in my Java code. (raspberrypi/phpmyadmin), (localhost:3306 returns: localhost refused to connect)

Here are some steps i’ve did:

  • opened the ports
  • changed the bind-adress from 127.0.0.1 to 0.0.0.0 in the mariadb settings
  • (skip-networking wasn’t even in my config) & set the port to 3306
  • added the mariadb-java-client-2.6 to my library in the java code

The main exception is: 

java.sql.SQLNonTransientConnectionException: Could not connect to address=(host=localhost)(port=3306)(type=master) : Socket fail to connect to host:localhost, port:3306. Connection refused: connect

everything else: 

at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.createException(ExceptionFactory.java:73)
    at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.create(ExceptionFactory.java:192)
    at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1346)
    at org.mariadb.jdbc.internal.util.Utils.retrieveProxy(Utils.java:634)
    at org.mariadb.jdbc.MariaDbConnection.newConnection(MariaDbConnection.java:150)
    at org.mariadb.jdbc.Driver.connect(Driver.java:89)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
    at sample.SQL.<init>(SQL.java:16)
    at sample.Login.initialize(Login.java:55)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2573)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2466)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3253)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3210)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3179)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3152)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3129)
    at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3122)
    at sample.Main.start(Main.java:16)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:919)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$11(PlatformImpl.java:449)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$9(PlatformImpl.java:418)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:417)
    at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:175)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.sql.SQLNonTransientConnectionException: Socket fail to connect to host:localhost, port:3306. Connection refused: connect
    at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.createException(ExceptionFactory.java:73)
    at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.create(ExceptionFactory.java:183)
    at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.createSocket(AbstractConnectProtocol.java:255)
    at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.createConnection(AbstractConnectProtocol.java:512)
    at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1341)
    ... 25 more
Caused by: java.net.ConnectException: Connection refused: connect
    at java.base/java.net.PlainSocketImpl.waitForConnect(Native Method)
    at java.base/java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:107)
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)
    at java.base/java.net.Socket.connect(Socket.java:609)
    at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.createSocket(AbstractConnectProtocol.java:250)
    ... 27 more

The refused connection sounds like a port or permission problem, but I’ve literally tried everything in the last asked questions here about this topic.

Thanks in advance for reading and any help 🙂

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Feeling so dumb right now.

    I once had another RaspberryPi connected, so all the time I opened the port on the wrong devices and even copied the wrong ip.

    After changing that I only had to fix the permission problem with: 

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

  2. 0

    can you try from a shell

    telnet <pi_IP> 3306

    This would show if the port is open at all. This would show, if your settings of the mariaDB server are at least open the port and the server is running. There could be still a firewall (eg. iptables or firewalld) running and prevent the port from being reached

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