The DNS request is made to the failed servers also. When the main server send the request to all the servers to notify their availability then the client looks the server instance using the JNDI lookup and search by using the object reference. This allows the user to find out the new server instance and it will then be passed to the stub that monitors the cluster and the list of the clusters gets updated and it shows the availability of the servers as well. If the request is made to the server that is failed then it can be handled by using the third party load balancer like Resonate, BigIP, etc. These products are used to mask multiple addresses in a single address and return the result. This helps in keeping the track of all the servers.