Lesson Learned #261: Java vs Permission denied: connect

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This post has been republished via RSS; it originally appeared at: New blog articles in Microsoft Community Hub.

Today, I worked on a service request that our customer got the following error message using Java code: 

Exception in thread "main" com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection to the host servername.database.windows.net, port 1433 has failed. Error: "Permission denied: connect. Verify the connect
ion properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall."


"Exception in thread "main" com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection to the host nodename.tenantring.northeurope1-a.worker.database.windows.net (redirected from servername.database.windows.
net), port 11001 has failed. Error: "Permission denied: connect. Verify the connection properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall.". at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:234)
at com.microsoft.sqlserver.jdbc.SQLServerException.ConvertConnectExceptionToSQLServerException(SQLServerException.java:285)
at com.microsoft.sqlserver.jdbc.SocketFinder.findSocket(IOBuffer.java:2462)
at com.microsoft.sqlserver.jdbc.TDSChannel.open(IOBuffer.java:668)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectHelper(SQLServerConnection.java:2695)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.login(SQLServerConnection.java:2362)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectInternal(SQLServerConnection.java:2213)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(SQLServerConnection.java:1276)
at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(SQLServerDriver.java:861)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)"


I would like to share with you what was my lessons learned here.


The first thing is to isolate the problem running the suggested Java code to see the results:




package testconnectionms; import java.sql.*; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.lang.model.util.ElementScanner6; import javax.sql.DataSource; /** * Simple connection test. * */ public class SQLTest { static { try { Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); } catch (Exception ex) { System.err.println("Unable to load JDBC driver"); ex.printStackTrace(); System.exit(1); } } public static void main(String[] args) throws SQLException { String username = "username"; String password = "Password"; String envname = "env"; String seconds = "10"; System.out.println("Arguements are: username="+username+",password="+password+",envname="+envname+",seconds="+seconds); String url = String.format("jdbc:sqlserver://servername.database.windows.net:1433;database=dbname;sslProtocol=TLSv1.2", envname,envname); System.out.println("-- Connecting to " + url); long start = System.currentTimeMillis(); Connection connection = DriverManager.getConnection(url, username, password); if (false) { } final long time1 = System.currentTimeMillis(); long time2 = time1; long cnt = 0; Integer secInt = Integer.valueOf(seconds); PreparedStatement st = connection.prepareStatement("SELECT * from demo"); st.setQueryTimeout(20); while (time1 + (secInt.intValue() * 1000) >= time2) { cnt++; ResultSet rs = st.executeQuery(); rs.next(); rs.close(); time2 = System.currentTimeMillis(); } st.close(); Long statementsCount = Long.valueOf(cnt); Long statementsPerSecond = Long.valueOf(cnt / ((time2 - time1) / 1000)); Double timePerStatement = Double.valueOf(1000.0 / (cnt / ((time2 - time1) / 1000.0))); System.out.println("statementsCount="+statementsCount); System.out.println("statementsPerSecond="+statementsPerSecond); System.out.println("timePerStatement="+timePerStatement); } private static void usage(String msg) { System.err.println("Usage: SQLTest -username username -password password -envname envname -seconds seconds"); System.err.println(msg); } }




The error message: Permission denied: connect reports that when when trying to open the port any firewall/NSG is blocking this outbound port, either, 1433 or redirect port 11000-12000.


If the issue is regarding with port 1433 means that the initial connection with port 1433 is rejecting, if the error message any port from 11000-12000 means that the issue is rejecting any of this port.


As a workaround, if your customer only has the port 1433 as outbound open, please, change the connection policy to Proxy meanwhile their networking team is opening as outbound connection from 11000-12000.


For reference: Azure SQL Database connectivity architecture - Azure SQL Database and Azure Synapse Analytics | Micr...



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