When you connect your network to the Internet or begin offering a substantial number of services on your corporate intranet, you’ll find that it’s beneficial to have your Domain Name Service (DNS) server(s) in-house. DNS is the process that’s used to resolve the name of a host that you’re trying to reach (for example, www.novell.com ) to an IP address (such as 220.127.116.11). The other routers on the Internet can use the IP address to help you get where you’re going. Prior to NetWare 5, putting the DNS server on a NetWare 5 server or administering it wasn’t easy. Administrators used UNIX, Linux, or NT to provide the DNS service—which meant that yet another platform was running in your computer room or data center.
In this Daily Drill Down, I’ll take you through the process of installing and configuring the DNS service on your NetWare 5 server. I’ll also show you how to set up a primary and secondary DNS server. Setting up a secondary DNS server will ensure that DNS services aren’t interrupted if the primary DNS server goes down or is unable to respond.
Installing DNS services
You have three options for installing DNS services on NetWare 5:
- Install during the initial NetWare 5 server installation
- Install with the NetWare installation program from the NetWare GUI
- Run DNIPINST.NLM
For the purposes of this drill down, I’ll assume that you already have NetWare 5 up and running and that you’ll use the DNIPINST.NLM to install the DNS services. From the NetWare 5 Console screen, type DNIPINST and press [Enter]. You should see the Novell DNS/DHCP Services Setup screen. Verify that the fully qualified NDS username, with appropriate rights to modify the NDS tree, is specified. Enter the password for this user and press [Enter] to log this NLM into the NDS tree. You’ll see a series of messages as the NDS schema is extended in order to provide the DNS service.
When this process is complete, you’ll see an NDS Context Query Form. This window asks you to position the Locator object, Group object, and RootServerInfo Zone object in your NDS tree. The Locator object holds the global defaults, a list of DNS servers, subnets, and zones in your tree. The Group object provides a way of getting information about any DNS-related object on the tree. The RootServerInfo Zone object points to the root DNS servers on the Internet so that you can get information about domains that you don’t maintain in your NDS tree. Verify that the correct NDS contexts are specified. (In my tree, I have only one context: NW5. All the data input fields will show O=NW5.) Now, click the Press Enter To Create The Objects button.
At this point, a series of messages will appear as the objects are created. Then, you’ll see a message telling you that you can run the Java-based DNS/DHCP Management Console to configure the DNS service that you’ve just installed. Press [Enter] and you’ll return to the NetWare 5 Console screen.
The next step is to install the DNS/DHCP Management Console. Go to the SYS:PUBLIC\DNSDHCP directory and run the SETUP.EXE program, which installs the DNS/DHCP Management Console to the local hard drive of the workstation upon which you’re running the Setup program. Running Setup also installs the necessary snap-ins so that NWAdmin can run the console, too. Specify where you want to store the files and click Next.
When installing the snap-ins for NWAdmin, you may have to browse to find the path for the files. If the destination screen shows no directory path for NWAdmin, you’ll need to enter one in order for the snap-ins to work correctly. If any read-only files are detected while Setup is installing the snap-ins, tell Setup to overwrite those files. If you don’t overwrite them, the DNS/DHCP Management Console may not operate in the way that you expect.
When the process has completed, you may want to review the readme file that applies to the DNS service. This file contains information for configuring the server properly or resolving problems. After you finish reading the file, close Notepad, and you’ll see a message that the DNS/DHCP Management Console setup is complete. Click OK to continue. Be sure to reboot your workstation after the management console has been installed.
Configuring the DNS service
To configure the DNS servers on your NetWare 5 server, you can use the DNSDHCP Java application that you’ll see on the desktop after you reboot the workstation. Or you can open NWAdmin and click Tools. Then, select DNS-DHCP Management Console to start the configuration process. Both of these options will get you to the same place. If you use the desktop Java application, you must specify the context of the NDS tree that it will be working with; if you use NWAdmin, that information is passed automatically to the Java application when NWAdmin calls for it.
First, you need to create a DNS Server object. This object designates a server in your tree that can respond to NDS requests from the workstations. To begin, click the Create icon on the toolbar to open the Create New DNS Record window. Select DNS Server and click OK. Use the browse button to the right of the Select Server Object field to browse the NDS tree. Then, select the server that you want to use. In the Host Name field, enter the name by which you want this host to be known on the Internet. In the Domain field, enter the DNS domain name in which this server will be. Click the Create button to finish creating the DNS Server object. At the bottom of the DNS/DHCP Management Console window, you should see an icon that reads DNS_servername, where servername is the NDS name of the server upon which you’re configuring DNS. Until the DNS server is running on that server, this icon will appear to have a slightly grayed-out look, and it will have an x through it.
Next, you’ll create a DNS Zone object. This object is an NDS container object that holds all the data for a particular DNS zone. Click the All Zones object on the left side of the DNS/DHCP Management Console; then, click the Create button on the toolbar. Select Zone from the list of options and click OK. When the Create Zone window appears, verify that the proper NDS context is shown. The Create New Zone option should be enabled. In the Zone Domain Name field, enter the name of the appropriate domain.
Now, you need to specify whether the zone type is primary or secondary. You can make NDS changes only to the primary zone. You can have a secondary zone only if a primary zone already holds the information that you want to make available. For our example, choose Primary.
At this point, you need to assign an Authoritative DNS server to this zone. Click the Authoritative DNS Server drop-down box and select the DNS server that you created just a few steps ago. Then, click the Create button to finish creating the zone record. A message will appear and remind you to create an A (DNS-speak for Address) record for the DNS server that you created and a corresponding PTR (pointer) record in the IN-ADDR.ARPA zone. Click OK to continue. To the left of the DNS/DHCP Management Console window, you’ll see an additional entry for the domain name for which you’ll resolve host names.
Creating DNS resource records
You’ll need to create a record that will allow an incoming request for a particular host name to be resolved to an IP address. As I’ve mentioned, the first step is to create an A record for the DNS server that we set up. Select the domain name record that you created at the left side of the console window and click the Create button on the toolbar. Resource Record, an additional menu option, will appear in the list of record types. Select Resource Record and click OK.
You’ll be dealing with several types of DNS records. The most common are A records that map a host name to an IP address. You’ll encounter several specialty type records, such as CNAME, MX, and NS. CNAME records allow a host to be known by more than one name on the Internet. An MX record is used by a mail server trying to send a message to a user in your domain; it tells the server where to find the mail server that’s handing e-mail for your domain. NS records identify those servers that can handle DNS inquiries for a domain.
In the Host Name field, enter the host name of the server upon which DNS services have just been installed. By default, the A record option should be enabled. Enter the IP address of this server in the Resource Record Data area of this window. Then, click the Create button to create the record.
You need to create a PTR record for this DNS server, too. Repeat the steps for opening the Create Resource Record window. This time, click the Others record type and click the PTR type. Back in the Create Resource Record window, enter the host name for the DNS server for which you created the A record. Enter the IP address, host name, and domain name in the Resource Record Data area. Finally, click the Create button to create the resource record.
Now, you’ll create an NS (DNS-speak for Name Server) record so that other servers trying to obtain name resolution information for your domain will know which server to ask for the information. The domain name with which you’re currently working should still be selected on the left side of the DNS/DHCP Management Console. Click the Create button on the toolbar, select Resource Record, and click OK. Click the Others record type, click the drop-down box, and select the NS record type. Enter the host name for this DNS server in the Host Name field. Enter the complete DNS server name in the DNS Server Domain Name field and click the Create button to create this NS record.
Creating an MX record for your mail server
One of the first records that you’ll create for your network will be an MX (Mail Exchange) record that will allow other companies and mail servers to know where to send mail for your domain. Start the process by selecting the domain that you’re working on in the left window of the DNS/DHCP Management Console. Next, click the Create button on the toolbar. When the Create New DNS Record window appears, select the Resource Record option and click OK.
When the Create Resource Record window appears, click the Others option and click the MX record option. In the Host Name field, enter the host name by which the mail server will be known on the Internet. It’s possible to have multiple MX records for a domain. For example, you may want to have more than one mail server that’s capable of handling mail for your domain. That way, if your primary ISP link goes down, you’ll have more than one path available to the mail server, and all mail can be routed automatically to the same mail server on a different IP address.
When you set up multiple MX records, assign a weight or order preference to each record so that the MX records are used in the order that you specify. A preference of 0 is handled first, 1 is handled next, and so forth. Also, enter the mail server’s name in the Exchange field. After clicking the Create button to place the MX record into the DNS servers database, don’t forget to create an A record to match the fully qualified domain name (for example, mail.domain.com) to the actual IP address used by the mail server.
It’s important to remember that, after you make any changes to the DNS database on your server, you must start and stop the DNS service to allow the server to reread its database and learn about the changes. Click the DNS server icon at the bottom of the DNS/DHCP Management Console window, click the Start/Stop Service button on the toolbar (it looks like a server icon with a small stop sign), and select Yes to stop the DNS service. Once the service has been stopped, you’ll notice that the icon’s stop sign has changed to a green light. Clicking this icon will restart the DNS service. Click Yes to confirm that you want to start the DNS service.
Starting the DNS service
To start the DNS service on a NetWare 5 server, go to the server’s console prompt window, type named, and press [Enter]. FourNLMs will load, and you’ll see two messages. The first message will indicate that the DNS service is listening on port 53, and the next message will indicate that the DNS service is starting for the primary zone (the DNS domain name—for example, ispsbs.com). Add the NAMED.NCF command to the server’s AUTOEXEC.NCF file so that the DNS service will start automatically each time that the server starts. Check the server’s command prompt window or view the SYS$LOG.ERR file to see if any errors occurred while you were starting up the DNS service.
Establishing a secondary DNS server
Once your primary DNS server is up and running, you’re ready to proceed with the installation and setup of the secondary DNS server. Don’t let the labels primary and secondary DNS server fool you. I’m aware of no practical limit to the number of DNS servers that you can have. Depending on the number of hosts in your domain that are listed on the DNS record—and the amount of incoming traffic to your domain—you may decide to have another DNS server or two to help handle the host-name-to-IP-address resolution process.
When you start the process of installing the secondary DNS server, you don’t have to start with DNIPINST.NLM because the NDS schema has already been extended and the base DNS NDS objects have already been created. You start by opening the DNS/DHCP Management Console application. Select the domain for which you’re creating a secondary DNS server and click the Create button on the toolbar. When the Create New DNS Record window appears, select the DNS Server option and click OK. Click the discovery button to the right of the Select Server Object field and browse the NDS tree to select the next NetWare 5 server to run DNS services. Once you’ve found the server, click it and click OK.
You don’t have to worry about reselecting a server that has already been configured to run DNS services. (If a server has already been configured to provide the DNS service, you’ll see three asterisks to the left of its name.) In the Host Name field, enter the host name by which this DNS server will be known. In the Domain field, enter the domain name in which this server will reside. Then, click the Create button.
As with the primary DNS server, you’ll create a PTR, an A, and an NS record in order for the server to become fully functional. With NT, you’d set up the domain name on the secondary DNS server and tell it where to look for the primary DNS record information. With NetWare 5 and the information that’s stored in NDS, all you have to do is create the secondary DNS server. Once the server is created, select the server name in the Available DNS Servers list and click the Add button to move it into the Authoritative DNS Servers column.
At this point, you need to start the DNS service on the secondary server with the NAMED.NCF command; then, add that command to the secondary server’s AUTOEXEC.NCF file. As with the primary DNS server, you’ll see a NAMED window on the server console that will provide details regarding the operation of the DNS service on this server. When you return to the DNS/DHCP Management Console window and click the secondary DNS Server icon, a message will appear indicating that the information is being refreshed and that detailed information about the server will be displayed shortly.
As you’ve seen in this Daily Drill Down, setting up your own DNS servers isn’t difficult. Maintaining and keeping the servers running will become less of a burden on your network staff.
Ronald Nutter is a senior systems engineer in Lexington, KY. He's an MCSE, Novell Master CNE, and Compaq ASE. Ron has worked with networks ranging in size from single servers to multiserver/multi-OS setups, including NetWare, Windows NT, AS/400, 3090, and UNIX. He's also the help desk editor for Network World. If you’d like to contact Ron, sendhim an e-mail . (Because of the large volume of e-mail that he receives, it's impossible for him to respond to every message. However, he does read them all.)The authors and editors have taken care in preparation of the content contained herein, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.