Using caching-only DNS servers  What is the best way to place
DNS servers in your intranet to serve your users'needs? Many DNS
servers exist to hold copies of an organization's zone files, as
you've seen if you've ever set up a DNS server. But a lot of DNS
servers hold no zones, living only to resolve names, whether on
the Internet ("What is the IP address of
http://www.microsoft.com?") or on your intranet ("Where is the
nearest DC for acme.com?"). Such a DNS server is called a
caching-only server. After you set up a zoneless DNS server, you
can see a reference to its caching-only nature in the event log
(event ID 708).  A caching-only server's strength lies, as its
name implies, in the fact that DNS servers remember the results
of previous resolutions. For example, if someone in your office
points his or her Web browser to http://www.cnn.com, the Web
browser asks its preferred local DNS server to find the IP
address of http://www.cnn.com from CNN.com's DNS server. The
preferred local DNS server goes out on t