There are five models of the Barracuda Spam Firewall. The entry level model handles 1-500 active email users and 1 million email messages per day. The largest model handles 8,000-22,000 active email users and 15 million email messages per day. These specifications are not limits of the system, but are the recommended capacity. Features: -Enterprise-class solution. -Full size 2U rackmount with rails. -15,000-30,000 active email users. -Web configuration interface. -Virus scanning of all incoming email messages and files. -Spam blocking. -Microsoft Exchange 5.5/2000/2003 LDAP Message Accelerator. -Per user settings and quarantine. -Redundant disk array for superior reliability. -Clustering for larger capacity and redundancy. -Two gigabit ethernet ports. -Hot swap redundant disk array (RAID). -Hot swap redundant power supply. -Per user score settings. -Customizable branding.