C#

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. C#

bool success = false;

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

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

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

success = mailman.SshOpenTunnel(sshHostname,sshPort);
if (success != true) {
    Debug.WriteLine(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("sshLogin","sshPassword");
if (success != true) {
    Debug.WriteLine(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.SmtpHost = "smtp.my-smtp-server.com";

//  Set the SMTP login/password (if required)
mailman.SmtpUsername = "smtpLogin";
mailman.SmtpPassword = "smtpPassword";

//  Create a new email object
Chilkat.Email email = new Chilkat.Email();

email.Subject = "This is a test";
email.Body = "This is a test";
email.From = "Chilkat Support <support@chilkatsoft.com>";
success = 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) {
    Debug.WriteLine(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.
Debug.WriteLine(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.  

Debug.WriteLine("Mail Sent!");