ThreatSentry - Version 3.0 ThreatSentry Host Intrusion Prevention + Application Firewall defends Windows Web servers against new and progressive attack techniques, protects network weak points, overcomes lapses in patch management, and reinforces regulatory compliance. An ISAPI filter hosted in MMC, ThreatSentry compares server requests to a knowledgebase and an evolving system baseline to detect untrusted activity and prevent attacks on Microsoft® IIS.