The VIRTBIZ spam and virus virtual appliance is a hosted solution designed to provide filtering of spam and malware before it is delivered to the receiving mail server. In this way, emails are filtered before reaching your delivery server thereby reducing management and server load on the receiving system. In effect, you can think of the solution as a "spam firewall".

Domain administrators can deploy the system without any changes to existing email infrastructure, making the solution fully compatible with any email service. There is nothing to change or install or maintain. Adding a domain to the filtering system is as easy as adding the domain to the filters and then making a change in the domain's MX record. All management functions of the system are controlled through a simple and easy to follow web interface. Permissions can be set for an unlimited number of users who can be given permission to view system-wide administrative functions, control only a domain or group of domains, or be restricted to a single email address. All users will be able to view reporting and statistics for the level of management they have been assigned.

Email is filtered in two stages. First, all inbound connections are subjected to DNS checks which ensure that the connecting system has a valid PTR (reverse DNS) and is not known to be a common source of spam. An estimated 60% of all spam is rejected at this level. That is because a great portion of the spam problem originates from infected PCs controlled as "zombies" or in a "botnet". Therefore, sources that are known to be a spam outlet are rejected. In addition, any IP address that does not have a valid PTR will be rejected, since that is a good indicator that no legitimate email should be sent from that connection.

If the sending system makes it through the first stage of checks, then email is allowed to the next stage where it is further checked against common DNS blacklists. A listing on one blacklist will result in the email being tagged as possible spam to undergo further analysis. A listing on two or more blacklists will tag the message with a high spam score, causing the message to be quarantined. Email is then sent through the system's heuristic engine which identifies suspicious messages.

Email that is marked as "clean" or "possible spam" will be delivered on to the receiving user. Email that has received a high spam score, or that contains a virus or malicious content (malware) is quarantined on the filtering system.

Main features:

• Displays the inbound/outbound mail queue size (currently for Sendmail/Exim users only), Load Average and Today’s Totals for Messages, Spam, Viruses and Blocked Content on each page header.
• Color-coded display of recently processed mail.
• Drill-down onto each message to see detailed information.
• Quarantine management allows you to release, delete or run sa-learn across any quarantined messages.
• Reports with customizable filters and graphs.
• Muliple user levels: user, domain and admin that limit the data and features available to each.