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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MS Windows Visual C/C++ Libraries

Linux/CentOS C/C++ Libraries

MAC OS X C/C++ Libraries

Solaris C/C++ Libraries

C++ Builder Libraries

#include <C_CkMailMan.h>
#include <C_CkEmail.h>

void ChilkatSample(void)
    {
    HCkMailMan mailman;
    BOOL success;
    const char * sshHostname;
    long sshPort;
    BOOL bSmtp;
    HCkEmail email;

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

    //  Any string argument automatically begins the 30-day trial.

    success = CkMailMan_UnlockComponent(mailman,"30-day trial.");
    if (success != TRUE) {
        printf("Component unlock failed\n");
        return;
    }

    //  Connect to an SSH server and establish the SSH tunnel:

    //  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 = CkMailMan_SshTunnel(mailman,bSmtp,sshHostname,sshPort);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        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 = CkMailMan_SshAuthenticatePw(mailman,bSmtp,"sshLogin","sshPassword");
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        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.
    CkMailMan_putSmtpHost(mailman,"smtp.chilkatsoft.com");

    //  Set the SMTP login/password (if required)
    CkMailMan_putSmtpUsername(mailman,"smtpLogin");
    CkMailMan_putSmtpPassword(mailman,"smtpPassword");

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

    CkEmail_putSubject(email,"This is a test");
    CkEmail_putBody(email,"This is a test");
    CkEmail_putFrom(email,"Chilkat Support <support@chilkatsoft.com>");
    CkEmail_AddTo(email,"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 = CkMailMan_SendEmail(mailman,email);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        return;
    }

    //  If you're curious, have a look at LastErrorText after
    //  a successful send.  You'll see detailed information that
    //  confirms the SSH tunneling.
    printf("%s\n",CkMailMan_lastErrorText(mailman));

    //  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.

    printf("Mail Sent!\n");

    CkMailMan_Dispose(mailman);
    CkEmail_Dispose(email);

    }