Mysql – how to diagnose a remote thesql database connection

How are you calling mysql_query()? I notice that you don't save the connection handle from the mysql_connect() call. It looks to me like the failing mysql_query() call is not using the connection you're making.

I recommend that you revise your code to do something like this:

function connect_db() {
    // Reads the config file
    include('system_config.php');

    if ($SYSTEM_DB_HOST == "") {
        return false;
    }

    $dbhandle = mysql_connect($SYSTEM_DB_HOST, $SYSTEM_DB_USER, $SYSTEM_DB_PASS);
    if ($dbhandle) {
        @mysql_select_db($SYSTEM_DB, $dbhandle);

        return $dbhandle;
    } else {
        return false;
    }
}

// ... invoke like this:
$dbhanle = connect_db();
if (!$dbhandle) {
    // handle failed DB connection
}

// later, whenever you need to run queries:
$result = mysql_query($querysql, $dbhandle);

This will ensure that the connection you make with mysql_connect is in fact the one that is used for the query. See if that changes anything; even if it doesn't, personally I think it's good practice to explicitly tell MySQL which DB connection you want to use.

Looks like you're doing everything right, except that the user that you're trying to use doesn't have privileges for connecting from localhost.

The SSH tunnel will mask your IP using the endpoint, in this case it's the localhost machine, you have several ways to solve this.

• Try to end the tunnel against another server that is in the same network, then you'll show up as connecting from that server

  sudo ssh -g -L3306:foreignserver.ip:3306 me@secondforeginserver.ip

• Add permissions to the localhost user, adding permissions for '%' never grants permissions for localhost

Let me know how it goes!