PacketSure 4.1 email security appliance from Palisade Systems excels at monitoring and blocking unacceptable e-mail message content. Utilizing User Datagram Protocol (UDP) packet inspection and TCP to check user behavior, the product gives administrators the power to prevent users from using file-sharing applications, running Windows file sharing, or visiting particular Web sites. On the downside, PacketSure does not have a quarantine capability for storage, review or release of messages that trigger a policy. Therefore, a company that needs to monitor messages for purposes of compliance may find the offering lacking in this regard. PacketSure, however, does a good job of securing data such as Social Security numbers, preventing transmission of intellectual property, and blocking unauthorized public instant messages and e-mail applications. The product offers a solid design in that it actually consists of two appliances: the PacketSure appliance that performs the actual policy enforcement, and the MCDR (Master Content Description Repository) appliance that resides inside the firewall, holding relevant policies. Users will find it easy to manage policies, but may find some difficulty in managing features and access to public IM applications. PacketSure also does not offer dedicated tools that can notify users of policy breaches, but it can be configured to send alerts by way of SMTP or Windows messaging.