How do I disable outbound Extended SMTP (ESMTP) in Microsoft Exchange 2000 Server?
Disabling outbound ESMTP in Exchange Server 5.5 requires a registry change, but Exchange 2000 includes a simple option to disable ESMTP from the SMTP connector. Open System Manager, open the SMTP connector's Properties dialog box, then go to the Advanced tab. Select the Send HELO instead of EHLO option. If the default SMTP connector is your only one, you might need to create a new SMTP connector. In most cases, though, this step is unnecessary. The Microsoft article "XCON: When to Create SMTP Connectors in Exchange 2000" (http://support.microsoft.com/default.aspx?scid=kb;en-us;q294736) describes many of the situations in which you'd need to create a new SMTP connector.