Say for example you have all your clients in an NT4 domain. And your internet domain ~web servers, ISA boxes, etc~ is running AD with your ISA servers in an array. Would Proxy clients ~not firewall or nat~ be able to utilize the load balancing/fault tolerance capabilities of the ISA Array? I am currently all NT4...both Internal and Internet domains. I am implementing ISA to replace our existing proxy server..however I have been tasked to implement fault tolerance with the ISA server itself. Load balancing would be nice..but fault tolerance is more what I am after. It does not seem that clustering is supported with ISA, yet NLB is an option. Anyone else had to implement ISA fault tolerance in an NT4 environment? Brian W. Rogers MCSE, MCT, MCP Client/Server Network Developer Tree of Life Corporation rogersb@xxxxxxxxxxxxxx office: (904)810-7334 mobile: (904)806-7173