Java 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. Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.DateTime;
import com.chilkatsoft.chilkat2.Socket;
import com.chilkatsoft.chilkat2.SshTunnel;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        SshTunnel tunnel = new SshTunnel();

        String sshHostname = "www.ssh-serverA.com";
        int sshPort = 22;

        // Connect to an SSH server and establish the SSH tunnel:
        try {
            tunnel.connect(sshHostname, sshPort);

            // Authenticate with the SSH server via a login/password
            // or with a public key.
            // This example demonstrates SSH password authentication.
            tunnel.authenticatePw("mySshLogin", "mySshPassword");

            // Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
            // with dynamic port forwarding:
            tunnel.setDynamicPortForwarding(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.setInboundSocksUsername("chilkat123");
            tunnel.setInboundSocksPassword("password123");

            // Start the listen/accept thread to begin accepting SOCKS proxy client connections.
            // Listen on port 1080.
            tunnel.beginAccepting(1080);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            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, 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.

        Socket tunnelB = new Socket();

        // Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
        tunnelB.setSocksHostname("localhost");
        tunnelB.setSocksPort(1080);
        tunnelB.setSocksVersion(5);
        tunnelB.setSocksUsername("chilkat123");
        tunnelB.setSocksPassword("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).
        try {
            tunnelB.sshOpenTunnel("www.ssh-serverB.com", 22);

            // Authenticate with ssh-serverB.com
            tunnelB.sshAuthenticatePw("uname", "pwd");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // 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
        Socket channel = new Socket();
        int maxWaitMs = 4000;
        boolean useTls = false;
        try {
            tunnelB.sshNewChannel("time-c.nist.gov", 37, useTls, maxWaitMs, channel);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // 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
        // true or false to indicate success.  If successful, the integer
        // is obtained via the ReceivedInt property.
        boolean bigEndian = true;
        try {
            channel.receiveInt32(bigEndian);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        DateTime dt = new DateTime();
        dt.setFromNtpTime(channel.getReceivedInt());

        // Show the current local date/time
        boolean bLocalTime = true;
        System.out.println("Current local date/time: " + dt.getAsRfc822(bLocalTime));

        // Close the SSH channel.
        try {
            channel.closeConnection(maxWaitMs);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Stop the background listen/accept thread:
        boolean waitForThreadExit = true;
        try {
            tunnel.stopAccepting(waitForThreadExit);

            // Close the SSH tunnel (would also kick any remaining connected clients).
            tunnel.closeTunnel(waitForThreadExit);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }
    }
}