The HP ProLiant DL320 Firewall/VPN/Cache Server running Microsoft Internet Security & Acceleration Server 2004 is an advanced firewall, VPN, and Web caching solution that can be quickly and easily deployed in multiple network environments to protect key business applications against new and emerging security threats.Flexible, feature rich and tight design integration with Microsoft Windows Server, Exchange Server, Outlook Web Access, Internet Information Services, and SharePoint Portal Server, ISA Server 2004 is one of the best application layer firewall, VPN solution for securing Windows networks.