ITA Secure Messaging provides best solution against spam available today for MS Exchange. ITA Secure Messaging works with all available versions for MS Exchange Servers including 5.5, 2000, and 2003. By tightly integrating with Microsoft Active Directory and utilizing a multi-pronged approach of detecting spam emails, ITA Secure Messaging becomes your best defense against spam. ITA Secure Messaging from an Exchange Admin's perpective ITA Secure Messaging is NOT implemented as an event sink. Therefore, no DLLs are installed on your Exchange server. Easy to install (and uninstall if need be) No need to reboot your Exchange server No registry settings are modified Easy to move ITA Secure Messaging's installation from one machine to another. Provides tools to monitor all e-mail coming in and out of your organization Although ITA Secure Messaging comes with built-in anti-virus protection, it works with any existing solution that you may have. Advantage of Active Directory Enhancement: Unlike other SMTP mail servers, MS Exchange do not reject emails coming to mailboxes that do not exist. Exchange Servers by default accept the mail for delivery and bounce the email later if the recipient mailbox is unavailable. Spam is often sent with fake sender email addresses that do not exist to recipients that are no longer valid, which results in many NDR's filling up the mail queue and taking up valuable cpu and storage resources. Using ITA Secure Messaging's Active Directory integration you can reject all mails that are addressed to mailboxes that do not exist and accept emails only for valid mailboxes that exist in the Active Directory. ITA Secure Messaging for MS Exchange uses a combination of well known effective filtering methods along with our own proprietary patent-pending Custom Rule Engine (CuRE ) technology for an effective spam solution. ITA Secure Messaging guarantees that it is the best product in the market for reducing and eliminating spam. ITA Secure Messaging also assures that your corporation will never loose a good email through our comprehensive system of email archiving and easy single-click restore option. Setup and installation takes only a few minutes and our anti-spam technology goes to work right away. Compatible with all Microsoft Exchange Servers including: Microsoft Exchange 5.5 Microsoft Exchange 2000 Microsoft Exchange 2003 ITA Secure Messaging is NOT an event sink ITA Secure Messaging is NOT implemented as an event sink for Exchange. Event sinks are programs that run inside Exchange's memory space. Here are some advantages of ITA Secure Messaging over another anti-spam product that are implemented as event sink. ITA Secure Messaging does not share the memory space with Exchange. Therefore, if more memory is used by Exchange, it does not affect ITA Secure Messaging and visa-versa. Memory corruption in either program does not affect the other. For more info search MSDN for "event sink memory". You do not have to install and register any DLLs with Exchange. No need to restart Exchange server or any other Windows Service. No registry entries are modified.