Open a Forwarded Channel through an SSH Tunnel

See more Socket/SSL/TLS Examples

Demonstrates Socket.SshNewChannel, which opens a port-forwarded channel through an authenticated SSH tunnel to a destination host and port, populating a Socket with the connected channel.

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Socket;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  socket: TSocket;
  sshPassword: string;
  bTls: Boolean;
  maxWaitMs: Integer;
  channel: TSocket;

begin
  success := False;

  socket := TSocket.Create;

  //  Connect to the SSH server and initialize an SSH tunneling session.  Port 22 is conventional but
  //  not required.
  success := socket.SshOpenTunnel('ssh.example.com',22);
  if (success = False) then
    begin
      WriteLn(socket.LastErrorText);
      Exit;
    end;

  //  Authenticate the SSH session before opening forwarded channels.
  //  The SSH password should come from a secure source rather than being hard-coded.
  sshPassword := 'mySshPassword';
  success := socket.SshAuthenticatePw('sshUser',sshPassword);
  if (success = False) then
    begin
      WriteLn(socket.LastErrorText);
      Exit;
    end;

  //  Open a port-forwarded channel through the authenticated SSH tunnel to the destination host and
  //  port, populating a Socket with the connected channel.  Set the 3rd argument to True to establish
  //  TLS to the destination inside the tunnel.
  bTls := False;
  maxWaitMs := 20000;
  channel := TSocket.Create;
  success := socket.SshNewChannel('db.internal',5432,bTls,maxWaitMs,channel);
  if (success = False) then
    begin
      WriteLn(socket.LastErrorText);
      Exit;
    end;

  //  Use the channel socket to send and receive with the destination through the tunnel.
  WriteLn('Forwarded channel opened to the destination.');


  socket.Free;
  channel.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.