The Internet Protocol Network Address Translator (IPNAT) is a kernel-mode driver that provides IP packet modification and filtering. This component is required to use Internet Connection Sharing, Internet Connection Firewall (ICF), Microsoft Routing and Remote Access Service (RRAS) NAT. Microsoft Internet Security and Acceleration Server (ISA) 2000 also requires this component.
As a kernel driver, IPNAT is not directly configured by the user. Various clients such as Connection Sharing, ICF, RRAS NAT, and ISA rely on IPNAT to load and configure the driver. All user-level configurations are exposed through the clients.