Lesson 2 in .NET framework

Printing QR in .NET framework Lesson 2

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The DNS namespace is hierarchical and is based on a unique root that can have any number of subdomains. An FQDN is a name of a DNS host in this namespace that indicates the host s location relative to the root of the DNS domain tree. An example of an FQDN is host1.subdomain.microsoft.com. A DNS zone is a contiguous portion of a namespace for which a server is author itative. A server can be authoritative for one or more zones, and a zone can con tain one or more contiguous domains. A DNS server is authoritative for a zone if it hosts the zone, either as a primary or secondary DNS server. Each DNS zone contains the resource records it needs to answer queries for its portion of the DNS namespace. The DNS Client service (or resolver) first attempts to resolve computer names using locally cached information, which includes the contents of the Hosts file. If the name cannot be found in the cache, the resolver queries a DNS server. If the DNS server cannot resolve the name through its authoritative records or through its local cache, the DNS server by default performs recursion to resolve the name on behalf of the client. Recursion is the process of a DNS server querying other servers on behalf of a DNS client. For the DNS server to perform recursion properly, the server needs to know where to begin searching for names in the DNS domain namespace. This information is provided by the root hints file, Cache.dns, that is stored on the server computer. A TTL value applies to all cached resource records. As long as the TTL for a cached resource record does not expire, a DNS server can continue to use that record to answer queries.

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Within private networks, DNS servers enable clients to resolve computer names defined within the private namespace. However, when DNS servers are properly configured and connected to the Internet, they can also allow clients to resolve Internetbased names without querying external name servers directly.

Install and configure a DNS server Create DNS zones and resource records Describe the difference between primary, secondary, caching-only, and stub servers Create a caching-only server Describe several of the most common types of resource records View and clear the DNS server cache

By default, all computers running Windows Server 2003 and Windows XP have the DNS Client service installed and running. However, the DNS Server service is not installed by default in any Windows operating system. To install the DNS Server service on a computer running Windows Server 2003, you first need to add the DNS server role through the Manage Your Server page. Once you have added this role, the DNS console appears in the Administrative Tools program group. The DNS console is the main tool for configuring and monitoring DNS servers, zones, domains, and resource records.

As an alternative to adding the DNS server role, you can install the DNS Server ser vice through Add Or Remove Programs in Control Panel. Select Add/Remove Windows Compo nents, and use the Windows Components Wizard to install the Domain Name System (DNS) subcomponent within the Networking Services Windows component.

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To install a DNS server, complete the following steps: 1. Insert the Windows Server 2003 installation CD-ROM into the computer on which you want to install a DNS server. 2. Verify that you have assigned the computer a static address. 3. Click Start and then click Manage Your Server to open the Manage Your Server page. 4. Click Add Or Remove A Role. 5. On the Preliminary Steps page of the Configure Your Server Wizard, follow the instructions, and then click Next. 6. On the Configuration Options page, select the Custom Configuration option, and click Next. 7. On the Server Role page, select DNS Server in the Server Role list, and then click Next. 8. In the Summary Of Selections page, click Next. When the DNS server component has finished installing, the Configure A DNS Server Wizard appears. 9. To configure the DNS server you have just installed, follow the prompts and accept all default settings to complete the Configure A DNS Server Wizard.