MailCloud uses Barracuda Networks firewall and spam solutions for inbound e-mail. This solution updates every 30 minutes via Barracuda's proprietary system for catching malicous e-mails and viruses. Without Barracuda, most anti-virus updates only occur daily at best. This ensures the fastest response to internet threats. We utilize HP's server line with the DL140, DL360 and DL380 servers. These servers feature redundant power supplies, dual-processor support and Raid. In addition, our experience with HP servers has been better than any other vendors products for dedicated systems including Dell. CentOS is the community enterprise operating system - based on RedHat Enterprise Server 4. Unlike other software distributions, CentOS features updates for years to come unlike Fedora or RedHat standard distributions. Security updates are supported for at least 5 years through RedHat. Qmail is the industry standard for high performance, robust and feature rich e-mail systems. Companies like Hotmail and Microsoft even utilize Qmail as their SMTP engine. In addition to it's proven security track, Qmail features a strong community involvement for features to come. Summary To sum this up, by offering our Barracuda + HP Servers + CentOS + Qmail = the highest scalable, secure E-mail solution on the Planet.