Microsoft small business knowledge base

Article ID: 317327 - Last Review: November 30, 2007 - Revision: 8.7

This article was previously published under Q317327
For a Microsoft Visual Basic Scripting Edition version of this article, see 317680  ( ) .

On This Page


This step-by-step article describes how to use an SMTP transport event sink to add a disclaimer to outgoing SMTP e-mail messages.

Create the event sink

  1. Create a new Microsoft Visual Basic ActiveX DLL. Name the project SMTPEventSink, and then name the module Disclaimer.
  2. Under Project References, add Microsoft CDO for Exchange 2000 Library, and then add Server Extension Objects COM Library.
  3. Put the following code in the module:
    Dim TextDisclaimer As String
    Dim HTMLDisclaimer As String
    Implements IEventIsCacheable
    Implements CDO.ISMTPOnArrival
    Private Sub IEventIsCacheable_IsCacheable()
        'Just returns S_OK.
    End Sub
    Private Sub Class_Initialize()
      'TODO: Replace the sample disclaimer text with your own text.
      TextDisclaimer = vbCrLf & "DISCLAIMER:" & vbCrLf & "Sample Disclaimer Text."
      HTMLDisclaimer = "<p></p><p>DISCLAIMER:<br>Sample Disclaimer Text"
    End Sub
    Private Sub ISMTPOnArrival_OnArrival(ByVal Msg As CDO.IMessage, EventStatus As CDO.CdoEventStatus)
        If Msg.HTMLBody <> "" Then
            Dim szPartI As String
            Dim szPartII As String
            Dim pos As Integer
            'Search for the "</body>" tag and insert the disclaimer before that tag.
            pos = InStr(1, Msg.HTMLBody, "</body>", vbTextCompare)
            szPartI = Left(Msg.HTMLBody, pos - 1)
            szPartII = Right(Msg.HTMLBody, Len(Msg.HTMLBody) - (pos - 1))
            Msg.HTMLBody = szPartI + HTMLDisclaimer + szPartII
        End If
        If Msg.TextBody <> "" Then
            Msg.TextBody = Msg.TextBody & vbCrLf & TextDisclaimer & vbCrLf
        End If
        'Commit the content changes to the transport ADO Stream object.
        EventStatus = cdoRunNextSink
    End Sub
  4. Replace the sample disclaimer text with your own disclaimer text, and then build the DLL.

Register the event sink

To register the event sink, use the Smtpreg.vbs file that is installed with the Exchange software development kit (SDK).
  1. At a command prompt, locate the \Exchange SDK\SDK\Support\CDO\Scripts folder, and then type the following: cscript smtpreg.vbs /add 1 OnArrival SMTPDisclaimer SMTPEventSink.Disclaimer "mail from=*"

    If this command succeeds, you receive a success message that is generated by the script.
  2. To unregister this event, type the following: cscript smtpreg.vbs /remove 1 OnArrival SMTPDisclaimer
For additional information about managing event bindings, visit the following Microsoft Developer Network (MSDN) Web site: (

Test the event sink

To test the event sink, send an e-mail message to an SMTP recipient who is external to your organization. The recipient receives a modified message with the disclaimer text added to the end of the message.

Note If you use a MAPI client, such as Microsoft Outlook, to send the e-mail message, the recipient does not receive a modified e-mail message. This is because the e-mail message that is submitted by using MAPI is not in an SMTP format when the e-mail message triggers the SMTP transport event. Therefore, changes that are made by the code of the event are not persisted.


For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
273233  ( ) Cannot change MAPI message contents in a CDO SMTP event sink

  • Microsoft Exchange Server 2003 Standard Edition
  • Microsoft Exchange Server 2003 Enterprise Edition
  • Microsoft Exchange 2000 Server Standard Edition
  • Collaboration Data Objects for Exchange 2000
  • Microsoft Collaboration Data Objects 2.0, when used with:
    • Microsoft Windows Server 2003, Standard Edition (32-bit x86)
    • the operating system: Microsoft Windows 2000
kbhowtomaster KB317327
Additional support options
Ask The Microsoft Small Business Support Community
Contact Microsoft Small Business Support
Find Microsoft Small Business Support Certified Partner
Find a Microsoft Store For In-Person Small Business Support