Java Requires Chilkat v11.0.0+

POP3 SSH Tunneling (Port Forwarding)

Demonstrates how to connect to a POP3 server through an SSH tunnel. Reads a POP3 mailbox and display the FROM and SUBJECT header fields of each email. Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Email;
import com.chilkatsoft.chilkat2.MailMan;

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.

        // The mailman object is used for receiving (POP3)
        // and sending (SMTP) email.
        MailMan mailman = new MailMan();

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

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

            // 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 POP3 server, it is
            // for authenticating with the SSH server, which is separate.
            mailman.sshAuthenticatePw("ssh_login", "ssh_password");

            // 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.

            // The SSH tunnel may be kept open for any number of
            // POP3 connections.

            // Set the POP3 server's hostname
            mailman.setMailHost("mail.my-pop3-server.com");

            // Set the POP3 settings for your POP3 server:
            mailman.setPopUsername("pop3_login");
            mailman.setPopPassword("pop3_password");
            mailman.setMailPort(995);
            mailman.setPopSsl(true);

            // Connect to the POP3 server through the already-established SSH tunnel:
            mailman.pop3BeginSession();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // A visual inspection of the LastErrorText after
        // a successful POP3 connection will confirm the SSH tunneling.
        // Note: If the POP3 connection uses SSL/TLS, then the SSL/TLS
        // secure channel will be wrapped within the SSH tunnel.
        System.out.println(mailman.getLastErrorText());

        // How many messages are in the POP3 inbox?
        int numToDownload = mailman.getMailboxCount();
        if (numToDownload > 5) {
            numToDownload = 5;
        }

        if (numToDownload == 0) {
            System.out.println("No messages in the POP3 inbox.");
            return;
        }

        // Download a max of 5 messages
        Email email = new Email();
        for (int i = 1; i <= numToDownload; i++) {
            try {
                mailman.fetchOne(false, 0, i, email);
            } catch (ChilkatException e) {
                System.out.println(e.getLastErrorText());
                return;
            }

            System.out.println(email.getFrom());
            System.out.println(email.getSubject());
            System.out.println("----");
        }

        // Close the connection with the POP3 server, leaving the SSH tunnel open for subsequent POP3 connections.
        try {
            mailman.pop3EndSession();

            // Try connecting to a different POP3 server through the same aleady setup SSH tunnel:
            // Set the POP3 server's hostname
            mailman.setMailHost("mail.my-pop3-server2.com");

            // Set the POP3 settings for your POP3 server:
            mailman.setPopUsername("pop3_login2");
            mailman.setPopPassword("pop3_password2");
            mailman.setMailPort(110);
            mailman.setPopSsl(false);

            mailman.pop3BeginSession();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Review the LastErrorText to see that the connection was made via the SSH tunnel:
        System.out.println(mailman.getLastErrorText());

        try {
            mailman.pop3EndSession();

            // Close the SSH tunnel.
            mailman.sshCloseTunnel();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }
    }
}