Platform: exchange 2013

We implemented a transport agent hook on OnRcptCommand hook point , which explained in Microsoft document , will be triggered when exchange server received RCPT command.   

http://msdn.microsoft.com/en-us/library/microsoft.exchange.data.transport.smtp.smtpreceiveagent.onrcptcommand.aspx

But during our test , we found that:

1. Using telnet to send mails using SMTP protocol, OnRcptCommand  will not be triggered even we input a valid "rcpt to:  <receiver>" command, but when do it on exchange 2010, OnRcptCommand  will be triggered as expected when input rcpt command.

2. When sending a mail having N recipients using outlook, OnRcptCommand  will be triggered exactly N times.

3. Each time the recipient count contained in the mailitem from this hook point will increase by one with starting count of 0.

So my question is why it behaves like above on exchange 2013. Why the behavior is different from document from Microsoft?

Hi Simon,

What's your objective / goal in developing an agent ?

I ask because most of the time a Routing Agent makes more sense than an STMP Receive Agent... and Routing Agents see ALL emails (even internal ones) in ALL versions of Exchange (well 2007-2013 anyway - there are different technologies for 2000 and 2003).

Regards,

Hi Scott,

My goal is to get the sender IP of a mail before exchange server receives the mail data of it, which, as depicted in Microsoft dev documents, could be achieved by using the RCPT command hook point.

But then, on E15, the issue described in my last note happened.

Best Regards.