C# SSH port forwarding with SSH.net

Question

I'm trying to do the following thing in a C# program with SSH.NET :

ssh -NfD 1080 username@remote.com

Here's the code I produced :

using (var client = new SshClient("remote.com", "username", "password"))
{
    client.Connect();
    var port = new ForwardedPortLocal("localhost", 1080, "remote.com", 1080);
    client.AddForwardedPort(port);

    port.Exception += delegate(object sender, ExceptionEventArgs e)
    {
         Console.WriteLine(e.Exception.ToString());
    };
    port.Start();
}
Console.ReadKey();

I connect to an OpenVPN server through this tunnel. When I use the command line it works fine, but when I use the C# program it's like the tunnel isn't working, even if I can send commands to the server I'm connected to through the C# program. Any idea ?

Not a single one. I have my program listening on 1080 but I can't use the tunnel. — il0venoobs, Dec 11 '14 at 11:18
so `Console.WriteLine(e.Exception.ToString());` never fires? — faby, Dec 11 '14 at 11:19
No. And when I send a command to the server, it works (for example pwd sends me back /home/username) — il0venoobs, Dec 11 '14 at 11:21
can you provide me an example of something that doesn't work? — faby, Dec 11 '14 at 11:23
I'm trying to connect to an OpenVPN server through the tunnel. It works well when I start the SSH tunnel manually (with ssh -NfD 1080 username@remote.com) but not when I use the C# application. — il0venoobs, Dec 11 '14 at 11:25
after `port.Start` try to check if `port.IsStarted` and let me know — faby, Dec 11 '14 at 11:29
IsStarted returns True and yes the remote address is correct. When I do Console.WriteLine(client.CreateCommand("pwd").Execute()); it returns /home/username so I'm connected to the server — il0venoobs, Dec 11 '14 at 11:52
did you try sending some command with `client.RunCommand("some command");` to see if it fails? — faby, Dec 11 '14 at 11:56
is it a possible solution to you to use this command? If yes I'll add an answer — faby, Dec 11 '14 at 11:59
Well I don't know. If I can still connect to my OpenVPN network through the tunnel then yes I guess — il0venoobs, Dec 11 '14 at 12:01
yes until you'll call the close method you will remain connected to your OpenVPN. Let me know if you need more help — faby, Dec 11 '14 at 12:07

score 1 · Answer 1 · answered Dec 15 '16 at 06:53

the Console.ReadKey(); should be placed in using block to ensure the SshClient instance is not disposed.

static void Main(string[] args)
    {
        using (var client = new SshClient("host", "name", "pwd"))
        {
            client.Connect();
            var port = new ForwardedPortDynamic(7575);
            client.AddForwardedPort(port);

            port.Exception += delegate (object sender, ExceptionEventArgs e)
            {
                Console.WriteLine(e.Exception.ToString());
            };
            port.Start();
            Console.ReadKey();
        }
    }

score 0 · Answer 2 · answered Dec 11 '14 at 12:05

0

As I suggested in comments I think that you can try to execute your commands with client.RunCommand method in this way

client.RunCommand("some command");

answered Dec 11 '14 at 12:05

faby

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score 0 · Answer 3 · answered Nov 13 '21 at 19:03

I found an answer thanks to da_rinkes on SSH.NET forum (link).

I was using ForwardedPortLocal instead of ForwardedPortDynamic (-D option with ssh command).

Here's the new code :

public void Start()
{
      using (var client = new SshClient("remote.com", "username", "password"))
      {
           client.KeepAliveInterval = new TimeSpan(0, 0, 30);
           client.ConnectionInfo.Timeout = new TimeSpan(0, 0, 20);
           client.Connect();
           ForwardedPortDynamic port = new ForwardedPortDynamic("127.0.0.1", 1080);
           client.AddForwardedPort(port);
           port.Exception += delegate(object sender, ExceptionEventArgs e)
           {
                Console.WriteLine(e.Exception.ToString());
           };
           port.Start();
           System.Threading.Thread.Sleep(1000 * 60 * 60 * 8);
           port.Stop();
           client.Disconnect();
     }
this.Start();
}

Still have to find another way to keep the SSH tunnel up (instead of a Sleep + recursive call every 8 hours).

_{Posted on behalf of the question asker}

C# SSH port forwarding with SSH.net

3 Answers3

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