Hi, I have exchange 2007 server installed and Loadgen installed on the same server and another client. When the test runs, the values of performance counters don't change. I tried the smtp module too. For this particular simulation, the values of the counters MsExchangeTransport SmtpReceive : Bytes Received Total , Bytes Receieved/Sec change .. but the values of MsExchangeTransport SmtpSend : BytesSent Total , Bytes Sent/Secdon't change. The generation of user accounts, initialization of the mailbox , generation of mails all succeed. Why does this happen. ?? Please help me out. Thanks in advance Subramanian.