system (PID 4) is listening on port 80

Microsoft Forefront ISA Server

Microsoft Forefront, formerly known as Internet Security and Acceleration Server (ISA Server), is a network router, firewall, antivirus program, VPN server and web cache that runs on Windows servers. It includes identity management and protection systems, and discontinued systems for threat management and network protection, along with protection for Sharepoint and Exchange. The scope of discussions includes forward and reverse proxy, application and service publishing, virtual private networks (VPNs), outbound access rules, SSL certificates and network routing within either a single node or an highly-available array pairing.