Visual Basic 6.0

Close the SSH Tunnel

Demonstrates the Chilkat MailMan.SshCloseTunnel method, which closes the SSH tunnel used for SMTP or POP3 communication. This example opens and authenticates a tunnel, performs a mail operation through it, and then closes it.

Background: An SSH tunnel holds an open connection to the SSH server for as long as it is needed, so closing it releases both that connection and the resources on the SSH server. The natural pattern is open → authenticate → do mail work → close. It is the counterpart to SshOpenTunnel, and is separate from closing the mail connections themselves (CloseSmtpConnection / Pop3EndSession), which ride inside the tunnel.

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Visual Basic 6.0

Dim success As Long
success = 0

'  Demonstrates the MailMan.SshCloseTunnel method, which closes the SSH tunnel used for SMTP
'  or POP3 communication.

Dim mailman As New ChilkatMailMan

'  Configure the POP3 server connection.
mailman.MailHost = "pop.example.com"
mailman.MailPort = 995
mailman.PopSsl = 1
mailman.PopUsername = "user@example.com"
mailman.PopPassword = "myPassword"

'  Open and authenticate the SSH tunnel.
success = mailman.SshOpenTunnel("ssh.example.com",22)
If (success = 0) Then
    Debug.Print mailman.LastErrorText
    Exit Sub
End If

success = mailman.SshAuthenticatePw("sshUser","sshPassword")
If (success = 0) Then
    Debug.Print mailman.LastErrorText
    Exit Sub
End If

'  ... perform mail operations through the tunnel ...
Dim count As Long
count = mailman.GetMailboxCount()
If (count < 0) Then
    Debug.Print "Failed to get the mailbox count."
Else
    Debug.Print "Mailbox count: " & count
End If

'  Close the SSH tunnel when finished with it.
success = mailman.SshCloseTunnel()
If (success = 0) Then
    Debug.Print mailman.LastErrorText
    Exit Sub
End If

Debug.Print "SSH tunnel closed."