Re: SMTP Protocol Event Sink to prevent mail from being sent

From: Chris Rose (ChrisRose_at_discussions.microsoft.com)
Date: 12/16/04 

Date: Thu, 16 Dec 2004 01:21:02 -0800

Victor,

Thanks for letting me know that the OnMessagePostCategorize event should
fire. I persisted with this and eventually worked out that it was because I
was registering the sink with the rule "mail from=*". I changed it to "RCPT
TO=*" and it fires everytime.

Regards,

Chris.

"Victor Ivanidze" wrote:

> Chris,
>
> OnMessagePostCategorize event is fired on my Exchange 2000 server machine
> when message is sent from Outlook to external Internet recipient.
>
> --
> Thanks and regards,
>
> Victor Ivanidze,
> software developer
> www.ivasoft.biz
>
>
> > Victor,
> >
> > Thanks but OnMessagePostCategorize is a Transport Event in the same family
> > as OnMessageSubmission and these don't appear to be firing on my exchange
> > 2000 server when mail is sent from Outlook (please let me know if you have
> > experienced different behaviour). Transport events do fire when I use
> telnet.
> >
> > The Protocol Events such as OnMessageStart do get fired for Outlook mail,
> so
> > I need to somehow delete the message using one of these protocol events.
> >
> > Regards,
> >
> > Chris.
> >
> > "Victor Ivanidze" wrote:
> >
> > > Try to use another event:
> > >
> > > STDMETHODIMP CSink::OnMessagePostCategorize(
> > > IMailMsgProperties *pMailMsg,
> > > IMailTransportNotify *pINotify,
> > > PVOID pvNotifyContext)
> > >
> > >
> > > --
> > > Regards,
> > >
> > > Victor Ivanidze,
> > > software developer
> > > www.ivasoft.biz
> > >
> > >
> > >
> > > "Chris Rose" <ChrisRose@discussions.microsoft.com> wrote in message
> > > news:E1E7F3F1-0769-46E5-8456-C3A86B2458B0@microsoft.com...
> > > > Hye,
> > > >
> > > > As a simple proof of concept I want to delete any outbound mail that
> is
> > > sent
> > > > from either Outlook or SMTP client if the subject does not contain the
> > > word
> > > > "Agreed".
> > > >
> > > > The following (VB COM DLL) Transport Event Sink works fine, so long as
> I
> > > > install it on a second Virtual SMTP server so that Outlook mail is
> relayed
> > > to
> > > > it in SMTP format.
> > > >
> > > >
> > > > Implements CDO.ISMTPOnArrival
> > > >
> > > > Private Sub ISMTPOnArrival_OnArrival(ByVal Msg As CDO.Message,
> EventStatus
> > > > As CDO.CdoEventStatus)
> > > >
> > > > Dim flds As ADODB.Fields
> > > >
> > > > Set flds = Msg.EnvelopeFields
> > > >
> > > > If Not InStr(Msg.Subject, "Agreed") > 0 Then
> > > >
> > > >
> > > >
> flds("http://schemas.microsoft.com/cdo/smtpenvelope/messagestatus").Value
> > > =
> > > > cdoStatAbortDelivery
> > > > flds.Update
> > > >
> > > > Msg.DataSource.Save
> > > >
> > > > sSender = Msg.From
> > > >
> > > > Dim oRejectionMessage As CDO.Message
> > > > Set oRejectionMessage = CreateObject("CDO.Message")
> > > > oRejectionMessage.To = sSender
> > > > oRejectionMessage.From = "MAILconsent"
> > > > oRejectionMessage.Subject = "Acceptable MAIL Usage Policy"
> > > > oRejectionMessage.TextBody = "Please read and agree to the
> policy
> > > > first."
> > > > oRejectionMessage.Send
> > > > Set oRejectionMessage = Nothing 'release the object
> reference
> > > >
> > > > End If
> > > >
> > > > End Sub
> > > >
> > > >
> > > > I don't really want to have a second SMTP server, so I decided to look
> > > into
> > > > Protocol Events instead as I learnt that GFI adds disclaimers in this
> way.
> > > I
> > > > implemented this in C#. The event fires for both Outlook and SMTP
> clients
> > > > which is exactly what I want, however I am unable to delete the
> message.
> > > Both
> > > > the AbortDelivery or BadMail message status' are ignored and the mail
> is
> > > > delivered.
> > > >
> > > > If I change the Recipients List to a known different recipient the
> mail is
> > > > delivered to the changed recipient so I know that I am kind of on the
> > > right
> > > > tracks. If I clear the list of recipients the mail is queued
> indefinitely
> > > and
> > > > seems to hold up all other mail.
> > > >
> > > > Here is the C# code:
> > > >
> > > > // registered for OnMessageStart event with the rule "mail from=*"
> > > > [Guid("679CD792-463D-4c9f-B47B-D997A67B97C4")]
> > > > public class SampleOutboundSink : ISmtpOutCommandSink
> > > > {
> > > > void ISmtpOutCommandSink.OnSmtpOutCommand(
> > > > object server,
> > > > object session,
> > > > MailMsg message,
> > > > ISmtpOutCommandContext context)
> > > > {
> > > > MailMsgPropertyBag Sever = new
> MailMsgPropertyBag(server);
> > > > MailMsgPropertyBag Session = new
> > > MailMsgPropertyBag(session);
> > > > Message Msg = new Message(message);
> > > > SmtpOutCommandContext Context = new
> > > > SmtpOutCommandContext(context);
> > > >
> > > > String strMessage;
> > > > if (Msg.Rfc822MsgSubject != null)
> > > > strMessage = Msg.Rfc822MsgSubject.ToString();
> > > > else
> > > > strMessage = "";
> > > >
> > > > // if not Agreed then do not send mail
> > > > if (strMessage.IndexOf("Agreed") == -1) {
> > > > // create a blank list of recipients to stop
> this
> > > > mail from being
> > > > // delivered
> > > > //RecipsAdd newRecips = Msg.AllocNewList();
> > > > //newRecips.AddSMTPRecipient("");
> > > > //Msg.WriteList(newRecips);
> > > >
> > > > Msg.MessageStatus =
> > > > Message.MessageStatusEnum.BadMail;
> > > > Msg.Commit();
> > > > }
> > > >
> > > > Context.CommandStatus = (uint)
> > > ProtocolEventConstants.S_OK;
> > > >
> > > > }
> > > > }
> > > >
> > > >
> > > > Any help on this would be greatly appreciated. And I apologise for
> posting
> > > a
> > > > similar message earlier in the Exchange 2000 Development forum.
> > > >
> > > > Regards,
> > > >
> > > > Chris.
> > > >
> > >
> > >
> > >
>
>

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