Delphi DLL Requires Chilkat v11.0.0+

SSH Tunnel Inside another SSH Tunnel

See more SSH Tunnel Examples

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

var
success: Boolean;
tunnel: HCkSshTunnel;
sshHostname: PWideChar;
sshPort: Integer;
tunnelB: HCkSocket;
channel: HCkSocket;
maxWaitMs: Integer;
useTls: Boolean;
bigEndian: Boolean;
dt: HCkDateTime;
bLocalTime: Boolean;
waitForThreadExit: Boolean;

begin
success := False;

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

tunnel := CkSshTunnel_Create();

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

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

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

//  Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
//  with dynamic port forwarding:
CkSshTunnel_putDynamicPortForwarding(tunnel,True);

//  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.

CkSshTunnel_putInboundSocksUsername(tunnel,'chilkat123');
CkSshTunnel_putInboundSocksPassword(tunnel,'password123');

//  Start the listen/accept thread to begin accepting SOCKS proxy client connections.
//  Listen on port 1080.
success := CkSshTunnel_BeginAccepting(tunnel,1080);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    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 := CkSocket_Create();

//  Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
CkSocket_putSocksHostname(tunnelB,'localhost');
CkSocket_putSocksPort(tunnelB,1080);
CkSocket_putSocksVersion(tunnelB,5);
CkSocket_putSocksUsername(tunnelB,'chilkat123');
CkSocket_putSocksPassword(tunnelB,'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 := CkSocket_SshOpenTunnel(tunnelB,'www.ssh-serverB.com',22);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnelB));
    Exit;
  end;

//  Authenticate with ssh-serverB.com
success := CkSocket_SshAuthenticatePw(tunnelB,'uname','pwd');
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnelB));
    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
channel := CkSocket_Create();
maxWaitMs := 4000;
useTls := False;
success := CkSocket_SshNewChannel(tunnelB,'time-c.nist.gov',37,useTls,maxWaitMs,channel);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnelB));
    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 := True;
success := CkSocket_ReceiveInt32(channel,bigEndian);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(channel));
    Exit;
  end;

dt := CkDateTime_Create();
CkDateTime_SetFromNtpTime(dt,CkSocket_getReceivedInt(channel));

//  Show the current local date/time
bLocalTime := True;
Memo1.Lines.Add('Current local date/time: ' + CkDateTime__getAsRfc822(dt,bLocalTime));

//  Close the SSH channel.
success := CkSocket_Close(channel,maxWaitMs);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(channel));
    Exit;
  end;

//  Stop the background listen/accept thread:
waitForThreadExit := True;
success := CkSshTunnel_StopAccepting(tunnel,waitForThreadExit);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;

//  Close the SSH tunnel (would also kick any remaining connected clients).
success := CkSshTunnel_CloseTunnel(tunnel,waitForThreadExit);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;

CkSshTunnel_Dispose(tunnel);
CkSocket_Dispose(tunnelB);
CkSocket_Dispose(channel);
CkDateTime_Dispose(dt);