I have been reading a great deal on this list about clusters, nlb's and arrays, but am not exactly sure what to do. I have isa running on a win2k stand alone server (in firewall/caching mode). It is also providing nat (via isa),dns and dhcp for the network. I am using active directory but not at the time the isa server was installed so it is not configured as an array. Failover/fault tolerancy/redundancy, whatever you want to call it, is needed. I first thought about getting another server and setting up an array but someone told me that an array does not provide failover capabilities. What is the best set up so if an isa server goes down another one will keep the network up? Thanks, Jim