Progent's E-Mail Guard is based on Postini's managed services, which utilize custom pass-through technology rather than the store-and-forward method for blocking spammers, e-mail viruses, DHA attacks, and Denial of Service Attacks. Under Postini's system, e-mail sent to your e-mail server is processed on the fly at Postini's secure Email Processing Center. Postini’s Connection Manager technology uses heuristic rules analysis to detect behavior patterns associated with DHA attacks and immediately filters DHA messages. Postini's Content Filter then isolates spam and viruses from benign messages by means of an in-memory procedure that requires only milliseconds.
