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?