(Unicode 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 <CkSshW.h>
#include <CkMailManW.h>
#include <CkEmailW.h>

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

    CkSshW ssh1;

    // Connect directly to the 1st SSH server.
    bool success = ssh1.Connect(L"serverssh1.com",22);
    if (success != true) {
        wprintf(L"%s\n",ssh1.lastErrorText());
        return;
    }

    // Authenticate using login/password:
    success = ssh1.AuthenticatePw(L"ssh1Login",L"ssh1Password");
    if (success != true) {
        wprintf(L"%s\n",ssh1.lastErrorText());
        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.
    CkSshW ssh2;
    success = ssh2.ConnectThroughSsh(ssh1,L"serverssh2.com",22);
    if (success != true) {
        wprintf(L"%s\n",ssh2.lastErrorText());
        return;
    }

    // Authenticate with ssh2...
    success = ssh2.AuthenticatePw(L"ssh2Login",L"ssh2Password");
    if (success != true) {
        wprintf(L"%s\n",ssh2.lastErrorText());
        return;
    }

    CkMailManW 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) {
        wprintf(L"%s\n",mailman.lastErrorText());
        return;
    }

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

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

    // Create a new email object
    CkEmailW email;

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

    success = mailman.SendEmail(email);
    if (success != true) {
        wprintf(L"%s\n",mailman.lastErrorText());
        return;
    }

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

    wprintf(L"Mail Sent!\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();
    }