Configuring DNS

Without DNS, computers would have a very tough time communicating with each other. However, most Windows administrators still rely on WINS for name resolution on local area networks and some have little or no experience with DNS. Steven Warren explains how to install, configure, and troubleshoot a Windows Server 2008 DNS server.

As many of you are probably aware, the Domain Name System (DNS) is now the name resolution system of choice in Windows. Without it, computers would have a very tough time communicating with each other. However, most Windows administrators still rely on the Windows Internet Name Service (WINS) for name resolution on local area networks and some have little or no experience with DNS. If you fall into this category, read on. We'll explain how to install, configure, and troubleshoot a Windows Server 2008 DN
Installtion

You can install a DNS server from the Control Panel or when promoting a member server to a domain controller (DC) (Figure A). During the promotion, if a DNS server is not found, you will have the option of installing it.

Figure A

Domain controller

To install a DNS server from the Control Panel, follow these steps:

From the Start menu, select | Control Panel | Administrative Tools | Server Manager.Expand and click Roles (Figure B).Choose Add Roles and follow the wizard by selecting the DNS role (Figure C).Click Install to install DNS in Windows Server 2008 (Figure D).

Figure B

Expand and click Roles

Figure C

DNS role

Figure D

Install DNS

DNS console and configuration

After installing DNS, you can find the DNS console from Start | All Programs | Administrative Tools | DNS. Windows 2008 provides a wizard to help configure DNS.

When configuring your DNS server, you must be familiar with the following concepts:

Forward lookup zoneReverse lookup zoneZone types

A forward lookup zone is simply a way to resolve host names to IP addresses. A reverse lookup zone allows a DNS server to discover the DNS name of the host. Basically, it is the exact opposite of a forward lookup zone. A reverse lookup zone is not required, but it is easy to configure and will allow for your Windows Server 2008 Server to have full DNS functionality.

When selecting a DNS zone type, you have the following options: Active Directory (AD) Integrated, Standard Primary, and Standard Secondary. AD Integrated stores the database information in AD and allows for secure updates to the database file. This option will appear only if AD is configured. If it is configured and you select this option, AD will store and replicate your zone files.

A Standard Primary zone stores the database in a text file. This text file can be shared with other DNS servers that store their information in a text file. Finally, a Standard Secondary zone simply creates a copy of the existing database from another DNS server. This is primarily used for load balancing.

To open the DNS server configuration tool:

Select DNS from the Administrative Tools folder to open the DNS console.Highlight your computer name and choose Action | Configure a DNS Server... to launch the Configure DNS Server Wizard.Click Next and choose to configure the following: forward lookup zone, forward and reverse lookup zone, root hints only (Figure E).Click Next and then click Yes to create a forward lookup zone (Figure F).Select the appropriate radio button to install the desired Zone Type (Figure G).Click Next and type the name of the zone you are creating.Click Next and then click Yes to create a reverse lookup zone.Repeat Step 5.Choose whether you want an IPv4 or IPv6 Reverse Lookup Zone (Figure H).Click Next and enter the information to identify the reverse lookup zone (Figure I).You can choose to create a new file or use an existing DNS file (Figure J).On the Dynamic Update window, specify how DNS accepts secure, nonsecure, or no dynamic updates.If you need to apply a DNS forwarder, you can apply it on the Forwarders window. (Figure K).Click Finish (Figure L).

Figure E

Configure

Figure F

Forward lookup zone

Figure G

Desired zone

Figure H

IPv4 or IPv6

Figure I

Reverse lookup zone

Figure J

Choose new or existing DNS file

Figure K

Forwarders window

Figure L

Finish

Managing DNS records

You have now installed and configured your first DNS server, and you're ready to add records to the zone(s) you created. There are various types of DNS records available. Many of them you will never use. We'll be looking at these commonly used DNS records:

Start of Authority (SOA)Name ServersHost (A)Pointer (PTR)Canonical Name (CNAME) or AliasMail Exchange (MX)

Start of Authority (SOA) record

The Start of Authority (SOA) resource record is always first in any standard zone. The Start of Authority (SOA) tab allows you to make any adjustments necessary. You can change the primary server that holds the SOA record, and you can change the person responsible for managing the SOA. Finally, one of the most important features of Windows 2000 is that you can change your DNS server configuration without deleting your zones and having to re-create the wheel (Figure M).

Figure M