VB.NET

IMAP SSH Tunneling (Port Forwarding)

Demonstrates how to setup and use an SSH tunnel for IMAP. VB.NET

Dim success As Boolean = False

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

Dim imap As New Chilkat.Imap

' 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).
Dim sshHostname As String = "www.mysshserver.com"
Dim sshPort As Integer = 22

' Connect to an SSH server and establish the SSH tunnel:
success = imap.SshOpenTunnel(sshHostname,sshPort)
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' 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 IMAP server, it is
' for authenticating with the SSH server, which is separate.
success = imap.SshAuthenticatePw("mySshLogin","mySshPassword")
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' OK, the SSH tunnel is setup.  The IMAP component may
' be used exactly the same as usual, except all communications
' are sent through the SSH tunnel.

' Connect to an IMAP server via the SSH tunnel.
' Because the SSH tunnel has been previously setup,
' this does not establish a direct connection with the IMAP
' server.  It directs the SSH server to establish the connection.

' In this example, the IMAP server requires SSL/TLS.  The TLS connection
' will be enclosed within the SSH tunnel.
imap.Ssl = True
imap.Port = 993
success = imap.Connect("imap.my-imap-server.com")
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' Authenticate with the IMAP server via the SSH tunnel.
success = imap.Login("myLogin","myPassword")
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' How many messages in Inbox?
Dim msgCount As Integer = imap.NumMessages
If (msgCount = 0) Then
    Debug.WriteLine("No messages found.")
    Exit Sub
End If


Dim upperBound As Integer = 10
If (msgCount < upperBound) Then
    upperBound = msgCount
End If


' Download up to the 1st 10 messages.
Dim email As New Chilkat.Email
Dim i As Integer
Dim bUid As Boolean = False
For i = 1 To upperBound


    success = imap.FetchEmail(False,i,bUid,email)
    If (success = False) Then
        Debug.WriteLine(imap.LastErrorText)
        Exit Sub
    End If


    Debug.WriteLine(email.From)
    Debug.WriteLine(email.Subject)
    Debug.WriteLine("----")
Next

' Disconnect from the IMAP server.
' The SSH tunnel remains open.
success = imap.Disconnect()
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' It is possible to re-use the existing SSH tunnel for the next connection:
success = imap.Connect("imap.my-imap-server2.com")
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' Review the LastErrorText to see that the connection was made via the SSH tunnel:
Debug.WriteLine(imap.LastErrorText)

success = imap.Disconnect()
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' Finally, close the SSH tunnel.
success = imap.SshCloseTunnel()
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("IMAP SSH tunneling example completed.")