Microsoft Internet Security and Acceleration (ISA) Server 2004 includes the following two components to prevent mail relaying, to prevent the entry of viruses, and to prevent unwanted mail attachments on the network:
| � | Simple Mail Transfer Protocol (SMTP) filter |
| � | Message Screener |
Message Screener is an optional ISA Server component that you can install separately. You must install Message Screener on a computer that is running Microsoft Internet Information Services (IIS) 6.0 or the Microsoft IIS 5.0 SMTP service.
Unlike Microsoft ISA Server 2000, Message Screener does not use DCOM to communicate with the ISA Server SMTP filter. ISA Server 2004 uses the Microsoft Firewall Control and remote procedure call (RPC) protocols on all interfaces to enable Message Screener to retrieve configuration information.