Java

SSH Tunnel with Dynamic Port Forwarding

See more SSH Examples

Demonstrates how to start a background thread that runs a portable SSH tunnel w/ dynamic port forwarding that the foreground thread can use for establishing connections through an SSH tunnel. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

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

    success = false;

    CkSshTunnel tunnel = new CkSshTunnel();

    String sshHostname = "sftp.example.com";
    int sshPort = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    success = tunnel.Connect(sshHostname,sshPort);
    if (success != true) {
        System.out.println(tunnel.lastErrorText());
        return;
        }

    // 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 != true) {
        System.out.println(tunnel.lastErrorText());
        return;
        }

    // Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
    // with dynamic port forwarding:
    tunnel.put_DynamicPortForwarding(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.

    tunnel.put_InboundSocksUsername("chilkat123");
    tunnel.put_InboundSocksPassword("password123");

    // Start the listen/accept thread to begin accepting SOCKS proxy client connections.
    // Listen on port 1080.
    success = tunnel.BeginAccepting(1080);
    if (success != true) {
        System.out.println(tunnel.lastErrorText());
        return;
        }

    // 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, 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.

    // For this example, let's do a simple HTTPS request:
    String url = "https://www.ethereum.org/";

    CkHttp http = new CkHttp();

    // Indicate that the HTTP object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
    http.put_SocksHostname("localhost");
    http.put_SocksPort(1080);
    http.put_SocksVersion(5);
    http.put_SocksUsername("chilkat123");
    http.put_SocksPassword("password123");

    http.put_SendCookies(true);
    http.put_SaveCookies(true);
    http.put_CookieDir("memory");

    // Do the HTTPS page fetch (through the SSH tunnel)
    String html = http.quickGetStr(url);
    if (http.get_LastMethodSuccess() != true) {
        System.out.println(http.lastErrorText());
        return;
        }

    // Stop the background listen/accept thread:
    boolean waitForThreadExit = true;
    success = tunnel.StopAccepting(waitForThreadExit);
    if (success != true) {
        System.out.println(tunnel.lastErrorText());
        return;
        }

    // Close the SSH tunnel (would also kick any remaining connected clients).
    success = tunnel.CloseTunnel(waitForThreadExit);
    if (success != true) {
        System.out.println(tunnel.lastErrorText());
        return;
        }
  }
}