SMTP SSH Tunneling (Port Forwarding)

Demonstrates how to setup an SSH tunnel for SMTP. This example connects to an SMTP sever via an SSH tunnel and sends an email.

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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[])
  {
    //  The mailman object is used for sending (SMTP) and receiving (POP3) email.
    CkMailMan mailman = new CkMailMan();

    //  Any string argument automatically begins the 30-day trial.
    boolean success;
    success = mailman.UnlockComponent("30-day trial.");
    if (success != true) {
        System.out.println("Component unlock failed");
        return;
    }

    //  Connect to an SSH server and establish the SSH tunnel:
    String sshHostname;
    int sshPort;
    boolean bSmtp;
    //  The SSH hostname may be a hostname or an
    //  IP address, such as "192.168.1.108".
    //  The port is typically 22 (the standard port for SSH).
    sshHostname = "www.my-ssh-server.com";
    sshPort = 22;
    bSmtp = true;
    //  The 1st argument passed to SshTunnel indicates whether
    //  a tunnel for SMTP or POP3 is being established.
    success = mailman.SshTunnel(bSmtp,sshHostname,sshPort);
    if (success != true) {
        System.out.println(mailman.lastErrorText());
        return;
    }

    //  Authenticate with the SSH server via a login/password
    //  or with a public key.
    //  This example demonstrates SSH password authentication.
    //  Note: This is not authenticating with the SMTP server, it is
    //  for authenticating with the SSH server, which is separate.
    success = mailman.SshAuthenticatePw(bSmtp,"sshLogin","sshPassword");
    if (success != true) {
        System.out.println(mailman.lastErrorText());
        return;
    }

    //  OK, the SSH tunnel is setup.  The mailman may
    //  be used exactly the same as usual, except all communications
    //  are now sent through the SSH tunnel.

    //  Set the SMTP server.
    mailman.put_SmtpHost("smtp.chilkatsoft.com");

    //  Set the SMTP login/password (if required)
    mailman.put_SmtpUsername("smtpLogin");
    mailman.put_SmtpPassword("smtpPassword");

    //  Create a new email object
    CkEmail email = new CkEmail();

    email.put_Subject("This is a test");
    email.put_Body("This is a test");
    email.put_From("Chilkat Support <support@chilkatsoft.com>");
    email.AddTo("Chilkat Admin","admin@chilkatsoft.com");

    //  The call to SendEmail automatically connects to the SMTP
    //  server via the SSH tunnel (if not already connected).
    //  Because the SSH tunnel has been previously setup,
    //  this does not establish a direct connection with the SMTP
    //  server.  It directs the SSH server to establish the connection.

    //  After SendEmail completes, the connection (i.e. session) remains
    //  open so that subsequent SendEmail calls may use the
    //  same SSH tunnel.
    success = mailman.SendEmail(email);
    if (success != true) {
        System.out.println(mailman.lastErrorText());
        return;
    }

    //  If you're curious, have a look at LastErrorText after
    //  a successful send.  You'll see detailed information that
    //  confirms the SSH tunneling.
    System.out.println(mailman.lastErrorText());

    //  Note: Some SMTP servers do not actually send the email until
    //  the connection is closed.  In these cases, it is necessary to
    //  call CloseSmtpConnection for the mail to be  sent.
    //  Most SMTP servers send the email immediately, and it is
    //  not required to close the connection.

    System.out.println("Mail Sent!");
  }
}