A signature-based antivirus solution will catch the majority of viruses, but it won't catch everything. Consequently, some companies use antivirus products from more than one vendor, or they might choose one product that includes multiple antivirus engines. Avinti CEO William Kilmer endorsed this layered approach in a conversation with us but said that one of those layers should look at behavior rather than signature in order to catch sophisticated, targeted attacks.
Avinti's iSolation Server 3.0 can sit behind an antivirus gateway or operate as the sole antivirus solution. iSolation Server first filters emails according to customer-defined policies and delivers messages whose attachments have an approved file type. Messages with questionable attachments are filtered by iSolation Server's Observation Engine, which opens the files in their appropriate applications and monitors them for potentially harmful behavior. Messages with files that pass Observation Engine inspection are delivered. Messages found to be harboring malware are quarantined.
Avinti says the iSolation Server can scale to handle more than 100,000 mailboxes and 1.5 million messages per day. It's available as a product or a hosted service. According to Kilmer, the rate of false positives is very low and processing messages can take from a few seconds to a minute. For more information, go to http://www.avinti.com.  
