A machine running client software can be configured to handle resolution using DNS, /etc/hosts, or NIS, or some combination of these three methods in a specified order.
If DNS is used, the IP addresses of the DNS name servers are configured in the /etc/resolv.conf file. A client can nominate itself (using the localhost or loopback address, 127.0.0.1) as a name server if it is configured as a DNS name server. Remote DNS name service only should be configured if a computer has limited memory or CPU power. In this case, all queries will be answered by a name server running on another computer on the network. In practice, however, you will obtain better performance by configuring the local machine as a caching-only name server. The resolver invoked by client programs does not cache replies because these programs tend to be short lived. Because a name server caches replies, all clients can take advantage of the data in its cache. Having a local name server avoids network traffic and propagation delays on subsequent queries to resolve the same IP addresses or host names.
The minimal configuration of the /etc.resolv.conf file to allow a host to perform a DNS look up on itself is:
nameserver 127.0.0.1
See ``The Client Manager interface'' for instructions on how to configure a name service client using the Client Manager.