In Microsoft window operating system the implementations of domain name system are given the name of “Microsoft DNS”. Two clients and a server are comprised by its derivatives window 2000, windows XP and windows 2003 as the domain name system supports Microsoft windows NT. Ordinary DNS looks up are performed by the DNS looks up clients that every Microsoft window machine has. Some machines are having Dynamic DNS clients that perform Dynamic DNS update transactions and register the machines names as well as IP addresses.
The software of a particular server is only supplied with the server versions of windows. The optional support of the local caching can also be had by the Microsoft’s DNS client. This is also known as DNSCACHE. The local IPC connection to the DNS client service on the machine is Attempted to be made before the direct communication with the DNS servers is tried to be made and if it is possible the job of dealing to the lookup is handed over to the DNS client service which itself communicate with the servers and the obtained results are cached. Microsoft DNS, s client does have the capability of talking to multiple DNS servers.
As far as the exact algorithm is concerned it varies according to the version and the service pack level of operating system. But generally all the primary DNS servers’ makes all the communication until it fails to answer and the process of communication switches to one of several alternative DNS servers. When the client service starts, the system behavior has lots of small differences depending on it. The lookup functions have get back to communicating the DNS servers by themselves if they cannot off-load their task onto the DNS client service. They lookup functions read only the host file where as the DNS client service only once reads the file at the start up and then re-reads it for just a single time after having noticed the last modification time of the file. The dosts file is read and parsed only a few times once at the start up and then at the time when DNS notices the last file’s modification time when the DNS client service is running.