(Delphi ActiveX) SSH Tunnel Inside another SSH Tunnel

Demonstrates how to create a TCP/IP socket connection through an SSH tunnel that is dynamic port forwarded through another SSH tunnel.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
tunnel: TChilkatSshTunnel;
sshHostname: WideString;
sshPort: Integer;
success: Integer;
tunnelB: TChilkatSocket;
channel: IChilkatSocket;
maxWaitMs: Integer;
useTls: Integer;
bigEndian: Integer;
dt: TCkDateTime;
bLocalTime: Integer;
waitForThreadExit: Integer;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// This example requires Chilkat version 9.5.0.50 or greater.
tunnel := TChilkatSshTunnel.Create(Self);

sshHostname := 'www.ssh-serverA.com';
sshPort := 22;

// Connect to an SSH server and establish the SSH tunnel:
success := tunnel.Connect(sshHostname,sshPort);
if (success <> 1) then
  begin
    Memo1.Lines.Add(tunnel.LastErrorText);
    Exit;
  end;

// Authenticate with the SSH server via a login/password
// or with a public key.  
// This example demonstrates SSH password authentication.
success := tunnel.AuthenticatePw('mySshLogin','mySshPassword');
if (success <> 1) then
  begin
    Memo1.Lines.Add(tunnel.LastErrorText);
    Exit;
  end;

// Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
// with dynamic port forwarding:
tunnel.DynamicPortForwarding := 1;

// We may optionally require that connecting clients authenticate with our SOCKS proxy server.
// To do this, set an inbound username/password.  Any connecting clients would be required to 
// use SOCKS5 with the correct username/password.
// If no inbound username/password is set, then our SOCKS proxy server will accept both
// SOCKS4 and SOCKS5 unauthenticated connections.

tunnel.InboundSocksUsername := 'chilkat123';
tunnel.InboundSocksPassword := 'password123';

// Start the listen/accept thread to begin accepting SOCKS proxy client connections.
// Listen on port 1080.
success := tunnel.BeginAccepting(1080);
if (success <> 1) then
  begin
    Memo1.Lines.Add(tunnel.LastErrorText);
    Exit;
  end;

// Now that a background thread is running a SOCKS proxy server that forwards connections
// through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
// such as HTTP, POP3, SMTP, IMAP, FTP, Socket, etc.  The protocol may use SSL/TLS because the SSL/TLS
// will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
// connections may be routed through the SSH tunnel.

tunnelB := TChilkatSocket.Create(Self);

// Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
tunnelB.SocksHostname := 'localhost';
tunnelB.SocksPort := 1080;
tunnelB.SocksVersion := 5;
tunnelB.SocksUsername := 'chilkat123';
tunnelB.SocksPassword := 'password123';

// Open a new SSH tunnel through the existing tunnel (via what we treat as a SOCKS5 proxy,
// but it is actually a dynamic port-forwarded SSH tunnel).
success := tunnelB.SshOpenTunnel('www.ssh-serverB.com',22);
if (success <> 1) then
  begin
    Memo1.Lines.Add(tunnelB.LastErrorText);
    Exit;
  end;

// Authenticate with ssh-serverB.com
success := tunnelB.SshAuthenticatePw('uname','pwd');
if (success <> 1) then
  begin
    Memo1.Lines.Add(tunnelB.LastErrorText);
    Exit;
  end;

// OK, the SSH tunnel (within a tunnel) is setup.  Now open a channel within the tunnel.
// Once the channel is obtained, the Socket API may
// be used exactly the same as usual, except all communications
// are sent through the channel in the SSH tunnel.
// Any number of channels may be created from the same SSH tunnel.
// Multiple channels may coexist at the same time.

// Connect to an NIST time server and read the current date/time

maxWaitMs := 4000;
useTls := 0;
channel := tunnelB.SshOpenChannel('time-c.nist.gov',37,useTls,maxWaitMs);
if (tunnelB.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(tunnelB.LastErrorText);
    Exit;
  end;

// The time server will send a big-endian 32-bit integer representing
// the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
// The ReceiveInt32 method will receive a 4-byte integer, but returns
// 1 or 0 to indicate success.  If successful, the integer
// is obtained via the ReceivedInt property.
bigEndian := 1;
success := channel.ReceiveInt32(bigEndian);
if (success <> 1) then
  begin
    Memo1.Lines.Add(channel.LastErrorText);

    Exit;
  end;

dt := TCkDateTime.Create(Self);
dt.SetFromNtpTime(channel.ReceivedInt);

// Show the current local date/time
bLocalTime := 1;
Memo1.Lines.Add('Current local date/time: ' + dt.GetAsRfc822(bLocalTime));

// Close the SSH channel.
success := channel.Close(maxWaitMs);
if (success <> 1) then
  begin
    Memo1.Lines.Add(channel.LastErrorText);

    Exit;
  end;

// Stop the background listen/accept thread:
waitForThreadExit := 1;
success := tunnel.StopAccepting(waitForThreadExit);
if (success <> 1) then
  begin
    Memo1.Lines.Add(tunnel.LastErrorText);
    Exit;
  end;

// Close the SSH tunnel (would also kick any remaining connected clients).
success := tunnel.CloseTunnel(waitForThreadExit);
if (success <> 1) then
  begin
    Memo1.Lines.Add(tunnel.LastErrorText);
    Exit;
  end;
end;