(VB.NET) 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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' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim ssh1 As New Chilkat.Ssh

' Connect directly to the 1st SSH server.
Dim success As Boolean = ssh1.Connect("serverssh1.com",22)
If (success <> True) Then
    Debug.WriteLine(ssh1.LastErrorText)
    Exit Sub
End If


' Authenticate using login/password:
success = ssh1.AuthenticatePw("ssh1Login","ssh1Password")
If (success <> True) Then
    Debug.WriteLine(ssh1.LastErrorText)
    Exit Sub
End If



' 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.
Dim ssh2 As New Chilkat.Ssh
success = ssh2.ConnectThroughSsh(ssh1,"serverssh2.com",22)
If (success <> True) Then
    Debug.WriteLine(ssh2.LastErrorText)
    Exit Sub
End If



' Authenticate with ssh2...
success = ssh2.AuthenticatePw("ssh2Login","ssh2Password")
If (success <> True) Then
    Debug.WriteLine(ssh2.LastErrorText)
    Exit Sub
End If


Dim mailman As New Chilkat.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) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If



' Set the SMTP server.
mailman.SmtpHost = "smtp.someserver.com"

' Set the SMTP login/password (if required)
mailman.SmtpUsername = "myUsername"
mailman.SmtpPassword = "myPassword"

' Create a new email object
Dim email As 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")

success = mailman.SendEmail(email)
If (success <> True) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


' Close the connection with the server.  This closes the tunnel through ssh2.
success = mailman.CloseSmtpConnection()
If (success <> True) Then
    Debug.WriteLine("Connection to SMTP server not closed cleanly.")
End If


Debug.WriteLine("Mail Sent!")



' 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()