High Availability By utilizing multiple front-end servers for inbound SMTP, outbound SMTP, POP and IMAP, this ensures services are up, not down. In addition, our use of high-quality HP servers instead of commodity hardware allows for high uptimes and low hardware failure rates. All servers feature RAID arrays for disk storage and redundant power supplies. We utilize private gigabit network filesystem arrays behind these front-end systems for added security. Data Backups Nightly backups for all mail storage data that resides on our systems. Performance Intel Xeon Systems with dual processor capability, Ultra 320 SCSI hard disks on HP 6i Raid controllers provide snappy, non laggy connections. Data Replication Services Our systems utilize a database backend with mySQL replication services, allowing each replicated server to utilize it's own local read database for delivery of e-mail. De-centralization of this service is a critical component to high availability and added scalability. Security Linux based firewall services to filter inbound threats. Software We utilize the Qmail e-mail server SMTP engine and Barracuda Networks firewall and spam server for inbound delivery. The Barracuda front-end inbound SMTP servers filter out unwanted e-mail and update every 30 minutes to minimize the impact of an internet virus from spreading to our system. Spam Filtering Numerous techniques are used here, including Sender Policy Framework (SPF), DomainKeys for SMTP authentication verification, Internet blacklists such as spamhaus.org and spamcop.net. In addition, spamassassin e-mail tagging is used to tag the headers of each individual e-mail for customized E-mail client filtering. Virus Scanning Barracuda Networks spam firewall server is used for in-bound SMTP delivery and ClamAV at the local SMTP outbound server.