VB.NET

POP3 over Multiple Hop SSH

Demonstrates how to read POP3 email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => POP3Server

VB.NET

Dim success As Boolean = False

' 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.
success = ssh1.Connect("serverssh1.com",22)
If (success = False) Then
    Debug.WriteLine(ssh1.LastErrorText)
    Exit Sub
End If


' Authenticate using login/password:
success = ssh1.AuthenticatePw("ssh1Login","ssh1Password")
If (success = False) 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 = False) Then
    Debug.WriteLine(ssh2.LastErrorText)
    Exit Sub
End If


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


Dim mailman As New Chilkat.MailMan

' Tell the mailman object to connect to the POP3 server though the ssh2 tunnel (which itself is routed through ssh1).
' The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => POP3Server
success = mailman.UseSsh(ssh2)
If (success = False) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


' Set the POP3 server's hostname
mailman.MailHost = "pop.example.com"

' Set the POP3 login/password.
mailman.PopUsername = "myLogin"
mailman.PopPassword = "myPassword"

' Establish the POP3 connection through the ssh2 tunnel.
success = mailman.Pop3BeginSession()
If (success = False) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


' Get the number of messages in the mailbox.
Dim numMessages As Integer = mailman.GetMailboxCount()

Dim email As New Chilkat.Email
Dim i As Integer = 1
While i <= numMessages
    ' Fetch by the message number (not by the UIDL)
    success = mailman.FetchOne(False,0,i,email)
    If (success = False) Then
        Debug.WriteLine(mailman.LastErrorText)
        Exit Sub
    End If


    Debug.WriteLine(email.From & ": " & email.Subject & vbLf)

    i = i + 1
End While

' Close the connection with the POP3 server.  (This closes the tunnel through ssh2)
' The connection with ssh2 is still alive, and may be used for more connections.
success = mailman.Pop3EndSession()

' 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()