I have a client computer getting an invalid page fault in negotiate.dll. A knowledgebase search reveals that the solution is to enable non-authenticated access in ISA. I don't really care for this idea. Do you know another way around the problem? Unfortunately we need the 3 components that collude together to create this problem. From MS Knowledgebase: The problem occurs only if all of the following conditions are true during an attempt to verify user credentials against a Microsoft Internet Security and Acceleration (ISA) server: The Directory Services Client for Windows is installed on the client computer. The Microsoft Firewall Client is installed on the client computer. The ISA server is set up as a firewall, and it requires client authentication (enforces user and group access policy through Site and Content Rules, and through Protocol Rules). CAUSE This issue occurs because the client authentication package references nonexistent memory while checking credentials. RESOLUTION To work around this issue, enable non-authenticated access.