In DNS Server we can configure a load balancing dns server usualy using round robin method which is spread the resource to any A Record ip server which have the same A Record. What i want is, i have primary web server and secondary(backup webserver). All user must directed to the primary web server when available, when not available user directed to secondary web server not load-balancing. Tks

You cannot do this with DNS. Round robin is not a true load balancing technique. The DNS server has no way of knowing if the primary web server is online and functioning. You can accomplish this by installing NLB on both web servers to create the virtual IP that both servers will share. otherwise, you'll need a hardware load balancer to accomplish this task. If you are interested in the software NLB (windows), you may want to post the question in the Clustering forum (HA) http://social.technet.microsoft.com/Forums/en-US/winserverClustering/threads. Also, for specific help with IIS, go to the official MS form: http://forums.IIS.net Visit: anITKB.com, an IT Knowledge Base.