“Unable to connect to any of the specified MySQL hosts” when connecting to MySQL database via SSH.NET tunnel in C#

Question

I'm trying to connect to a MySQL DB running on Ubuntu using C# and SSH.Net.

Our MySQL DB only allows connections from a webserver and going by what I can see from the code below, the client object connects to the webserver and then I open a port to map to 3306 on the DB server. Finally the MySQLConnection object opens a connection to the MySQL DB.

However I get with exception in sql.Open() statement:

Unable to connect to any of the specified MySQL hosts

I've checked other threads on the same subject and tried their suggestions, but none of them seem to help me.

• Unable to connect to any of the specified MySQL hosts

• Unable to connect to any of the specified MySQL hosts

• unable to connect to any of the specified MySQL hosts

and many more.

Here is some test code that I'm using -

var ci =
     new ConnectionInfo(
         "server", "userid", new PasswordAuthenticationMethod("userid", "userpwd"));
using (var client = new SshClient(ci))
{
    client.Connect();
    if (client.IsConnected) //This part works fine - I can connect to my Webserver.
    {
        //not sure if this is correct in our context.
        var local = new ForwardedPortDynamic("127.0.0.1",3306); 
        client.AddForwardedPort(local);
        try
        {
            local.Start();
        }
        catch (SocketException se)
        {

        }
        string connStr =
            "Server = dbserver;Port = 3306;Database = dbname;Uid = dbuserid;Pwd = dbpwd;";
        MySqlConnection sql = new MySqlConnection(connStr);

        try
        {
            sql.Open();
            local.Stop();
        }
        catch (MySqlException se)
        {
        }
    }
}

All of the credentials I've put in my code was taken off a working MySQLWorkbench connection to the MySQL DB.

I work exclusively in a Windows environment, so if you want me to check for something on the Ubuntu server please also tell me, if possible, how to check for it.

Answer 1

You are connecting via an SSH tunnel.

So your primary problem is that the Host in the connection string must be localhost (the local end of the SSH tunnel), not dbserver . Or even better, use ForwardedPort.boundHost (and ForwardedPort.boundPort ).

---

The second problem is that you cannot use ForwardedPortDynamic , but ForwardedPortLocal .

---

var forwardedPort = new ForwardedPortLocal("127.0.0.1", "127.0.0.1", 3306);

client.AddForwardedPort(forwardedPort);
forwardedPort.Start();

string connStr =
    string.Format(
        "Server = {0};Port = {1};Database = dbname;Uid = dbuserid;Pwd = dbpwd;",
        forwardedPort.BoundHost, forwardedPort.BoundPort);

---

See also Connection to MySQL from .NET using SSH.NET Library .

---

If your database does not run on the webserver, but on dbhost , you have to use that in the ForwardedPortLocal constructor:

var forwardedPort = new ForwardedPortLocal("127.0.0.1", "dbhost", 3306);