(VB.NET) Bounced Email Handling

Demonstrates how to examine emails and detect which are bounced (automated) replies. Classifies each email according to the type of bounce.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

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

Dim bounce As New Chilkat.Bounce

' The mailman object is used for receiving (POP3) 
' and sending (SMTP) email.
Dim mailman As New Chilkat.MailMan

' Set the POP3 server's hostname
mailman.MailHost = "mail.chilkatsoft.com"

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

' Copy the all email from the user's POP3 mailbox 
' into a bundle object.  The email remains on the server.
' (There are other methods for deleting email from a POP3 server.)
Dim bundle As Chilkat.EmailBundle = mailman.CopyMail()
If (mailman.LastMethodSuccess = False) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


Dim i As Integer = 0
Dim email As Chilkat.Email
While i < bundle.MessageCount
    email = bundle.GetEmail(i)

    Dim success As Boolean = bounce.ExamineEmail(email)
    If (success = False) Then
        Debug.WriteLine(bounce.LastErrorText)

        Exit Sub
    End If


    If (bounce.BounceType = 1) Then
        ' Hard bounce, log the email address
        Debug.WriteLine("Hard Bounce: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 2) Then
        ' Soft bounce, log the email address
        Debug.WriteLine("Soft Bounce: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 3) Then
        ' General bounce, no email address available.
        Debug.WriteLine("General Bounce: No email address")
    End If

    If (bounce.BounceType = 4) Then
        ' General bounce, log the email address
        Debug.WriteLine("General Bounce: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 5) Then
        ' Mail blocked, log the email address
        ' A bounce occured because the sender was blocked. 
        Debug.WriteLine("Mail Blocked: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 6) Then
        ' Auto-reply, log the email address
        Debug.WriteLine("Auto-Reply: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 7) Then
        ' Transient (recoverable) Failure, log the email address
        Debug.WriteLine("Transient Failure: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 8) Then
        ' Subscribe request, log the email address
        Debug.WriteLine("Subscribe Request: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 9) Then
        ' Unsubscribe Request, log the email address
        Debug.WriteLine("Unsubscribe Request: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 10) Then
        ' Virus Notification, log the email address
        Debug.WriteLine("Virus Notification: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 11) Then
        ' Suspected bounce.
        ' This should be rare.  It indicates that the Bounce
        ' component found strong evidence that this is a bounced
        ' email, but couldn't quite recognize everything it
        ' needed to be 100% sure.  Feel free to notify
        ' support@chilkatsoft.com regarding emails having this
        ' bounce type.
        Debug.WriteLine("Suspected Bounce!")
    End If

    If (bounce.BounceType = 12) Then
        ' Challenge/Response - Auto-reply message sent by SPAM software 
        ' where only verified email addresses are accepted. 
        Debug.WriteLine("Challenge: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 13) Then
        ' Address Change Notification Message.
        Debug.WriteLine("Address Change: " & bounce.BounceAddress)
    End If

    If (bounce.BounceType = 14) Then
        ' Success DSN indicating that the message was successfully relayed.
        Debug.WriteLine("DSN Successful Relay: ")
    End If




    i = i + 1
End While



success = mailman.Pop3EndSession()