When a Windows 2000 DNS server responds to DNS queries, it
doesn’t respond with the first corresponding record. Instead, it responds with
records in turn, cycling through the matching records in what’s referred to as
round robin DNS.

The result
of round robin DNS is that one client receives the first host record, the next
receives the second, and so on. In effect, round robin DNS points clients to
different host IP addresses for the same host name.

Round
robin DNS provides a simple mechanism for load balancing between servers that
supply the same resource, such as a Web site. For example, if your existing Web
server begins to experience a relatively high workload, you might consider putting
in another server, duplicating the content, and load-balancing the requests for
the site across the two servers. Using round robin DNS to load-balance the traffic is one very quick
solution for equalizing server load.

However, in some situations, you might not want to load-balance
queries in this way. For example, you might prefer to use a primary server as
long as it’s available, only using secondary servers when a primary server
drops offline.

If this is the case, you can disable round robin DNS, and
the DNS service will return the list of hosts in the same order as they exist
in the zone. Keep in mind that you can only enable or disable round robin on a
per-server basis; you can’t control round robin at the zone level.

To disable round robin DNS in Windows 2000 Server, follow
these steps:

  1. Open
    the DNS console.
  2. Right-click
    the appropriate server, and choose Properties.
  3. On the
    Advanced tab, deselect the Enable Round Robin check box, and click OK.

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