(C++) SMTP over Multiple Hop SSH

Demonstrates how to send email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => SmtpServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

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#include <CkSsh.h>
#include <CkMailMan.h>
#include <CkEmail.h>

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

    CkSsh ssh1;

    // Connect directly to the 1st SSH server.
    bool success = ssh1.Connect("serverssh1.com",22);
    if (success != true) {
        std::cout << ssh1.lastErrorText() << "\r\n";
        return;
    }

    // Authenticate using login/password:
    success = ssh1.AuthenticatePw("ssh1Login","ssh1Password");
    if (success != true) {
        std::cout << ssh1.lastErrorText() << "\r\n";
        return;
    }

    // Connect through the 1st SSH connection to reach a 2nd SSH server.
    // Note: Any number of SSH connections may be simultaneously tunneled through a single
    // existing SSH connection.
    CkSsh ssh2;
    success = ssh2.ConnectThroughSsh(ssh1,"serverssh2.com",22);
    if (success != true) {
        std::cout << ssh2.lastErrorText() << "\r\n";
        return;
    }

    // Authenticate with ssh2...
    success = ssh2.AuthenticatePw("ssh2Login","ssh2Password");
    if (success != true) {
        std::cout << ssh2.lastErrorText() << "\r\n";
        return;
    }

    CkMailMan mailman;

    // Tell the mailman object to connect to the SMTP server though the ssh2 tunnel (which itself is routed through ssh1).
    // The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => SMTPServer
    success = mailman.UseSsh(ssh2);
    if (success != true) {
        std::cout << mailman.lastErrorText() << "\r\n";
        return;
    }

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

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

    // Create a new email object
    CkEmail email;

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

    success = mailman.SendEmail(email);
    if (success != true) {
        std::cout << mailman.lastErrorText() << "\r\n";
        return;
    }

    // Close the connection with the server.  This closes the tunnel through ssh2.
    success = mailman.CloseSmtpConnection();
    if (success != true) {
        std::cout << "Connection to SMTP server not closed cleanly." << "\r\n";
    }

    std::cout << "Mail Sent!" << "\r\n";

    // Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
    // The connection with ssh1 is still alive, and may be used for more connections.
    ssh2.Disconnect();

    ssh1.Disconnect();
    }