A second IIS5 SMTP virtual server installed and running as an SMTP relay on your Exchange 2000 server. This virtual server must have an IP assigned to it - This means that the MX record of your domain must be pointing to the IP of this second virtual server. For more information about this: http://support.microsoft.com/support/kb/articles/Q293/8/00.ASP
To receive messages from users sending mails in Exchange 5.5 RTF format: Microsoft Outlook 2000 OR the Windows Messaging components installed on the Mail essentials machine. Note that Microsoft Outlook must be set as the default mail client! Make sure Outlook express does not set itself as the default mail client. The Windows 2000 messaging components are supplied by Microsoft, but can be downloaded from the GFI Mail essentials support page. For more information http://support.microsoft.com/support/kb/articles/Q254/4/58.ASP
