The support of DNS function with the DNS Server service provides name resolution for Microsoft« Windows 2000 Professional and Windows XP Professional client computers. When a client needs to find a computer, it queries the DNS service on the Small Business Server computer. If the computer name is found, the DNS service returns the IP address; otherwise, the request is forwarded to the Internet service provider (ISP) using configured forwarders.

A local DNS server improves query performance for local network resources without requiring an external query to your ISP's DNS servers. To resolve queries for Internet resources, your DNS server is configured to forward the queries to your ISP's DNS servers. By using your ISP's DNS servers for name resolution, you do not have to manage DNS records for Internet resources.
In addition to providing name resolution, the DNS Server service is required to support Active Directory.

When you run Setup and the Small Business Server Internet Connection Wizard to configure DNS, the following changes are made:

• To prevent your DNS server from resolving queries for Internet resources, the root zone automatically created when DNS is installed is deleted.
• To prevent your DNS server from resolving Internet DNS queries, DNS is configured to listen only for local network DNS queries. The DNS service is bound to the local network IP address only.
• So that your DNS server can resolve your local client computer's reverse queries, a reverse lookup zone is created. A reverse query resolves the Internet Protocol (IP) address to the fully qualified domain name (FQDN).
• The Small Business Server Internet Connection Wizard creates forwarders so that name resolution requests intended for the Internet are forwarded to your ISP's DNS servers. Using forwarders makes internal name resolution more efficient and keeps your internal host information from being broadcast over the Internet.

• Trace DNS Local Server