Chapter 2 - Creating and Configuring Domain Name System (DNS) Servers
In some cases, NetWorker for NT requires the use of a Domain Name System (DNS). A DNS provides a translation of a symbolic host name to the Internet Protocol (IP) address of the host. DNS essentially functions as a names server, or database, of IP addresses and their corresponding symbolic host names.
This section describes some aspects of DNS.
If you do not have a DNS, you can create your own DNS or you can use (and modify) one of several public Domain Name Systems available via the Internet.
You must create a DNS server if you are attempting to do any of the following:
You want to allow NetWorker running on a Windows NT server to communicate with an EBR agent running on a VINES server on one segment. The DNS enables your Windows NT server to communicate with your VINES server. You want to allow two or more Windows NT servers, on different segments, to communicate and you have decided not to use the host tables. You do not need to create a DNS if you want to allow two Windows NT servers on the same segment to communicate. Windows NT uses a host table to allow servers to communicate in a pure NT environment. The host table is there by default, but is not populated. If you want to use the existing host table, you must edit the host file to include the hosts you are working with.
Prior to creating a DNS server:
You need an IP address for your host machine. The server's TCP/IP software requires the IP address. You must also enter the IP address while editing your DNS configuration files. You need a domain name. During the TCP/IP configuration process you must enter the domain name. You must also enter the domain name while editing your DNS configuration files. All VINES and Windows NT servers must be running TCP/IP.
Before creating a DNS, you need to be familiar with domain names and IP addresses, as well as how to obtain a registered domain name and a valid IP address.
To create a DNS, you need a domain. A domain identifies a particular partition in the domain name system; each domain is assigned a unique domain name. If you will be using your computer to access information on the Internet, you will need a registered domain name. To obtain a registered domain name, you must complete a U.S. Domain Template by sending a message to the US domain registrar (us-domain@isi.edu), or by contacting USC/Information Sciences Institute at (301) 822-1511.
If you will not be accessing information outside of your own in-house network, you do not need a registered domain name. Instead, your domain name only needs to be unique within your own network.
Note: If in the future you will be using your host to access information outside of your own network, such as accessing the Internet, you should obtain a registered domain name now before you set up your DNS. Otherwise, when you do obtain a registered domain name, you will have to set up your DNS again to reflect your new registered domain name.
Internet Protocol (IP) Addresses
While setting up a DNS, you will be asked to enter an IP address for your host machine so that it can be identified during network communication sessions. An IP address is a logical 32-bit address used to identify physical networks.
The 32-bit (4 byte) IP address is usually represented by four integers separated by three dots. Each integer represents the value of one byte, and can range from 0 through 255 (0 and 255 are usually reserved for special operations). For example:
128.45.67.89
Depending on the particular address, the first one, two, or three numbers represent the unique network identification number. A given network may then divide the remaining address into a subnet identification number and the machine, or host, identification number. For the example above, a typical network would have a network ID number of 128.45 and might be set up to use the third number (67) as a subnet and the fourth number (89) as the host ID.
Obtaining a Valid IP Address
If you are going to connect to other networks outside of your own, such as the Internet, you will need to obtain a valid IP address. Your IP address will be unique across all networks and will also be assigned a class. To obtain a unique valid IP address, contact the Internet Address Network Authority (IANA):
Network Solutions
InterNIC Registration Services
505 Huntmar Park Drive
Herndon, VA 22070
If you are not going to use your network to connect to other networks, such as the Internet, you do not need to obtain a valid IP address. Instead, you can create and assign your own IP address for the host machines on your networks.
Note: If you are going to connect to other networks, such as the Internet, you should obtain valid IP addresses before creating a DNS or installing TCP/IP. If you obtain valid IP addresses, you will not have to reassign IP addresses later, remove your DNS that has the invalid IP addresses, and create another DNS using valid IP addresses.
In some organizations, it may be necessary to have one network with one or more subnets on that network. A subnet allows you to create several small networks, using the same network ID, instead of one large network. The network and each of its subnets has its own unique subnet ID assigned to it, although they all have the same network ID. Using subnets is often beneficial when there are substantial security concerns arising from having all users accessing one network. Refer to "Internet Protocol (IP) Addresses" earlier in this section for information on which bytes in an IP address are the subnet identification.
Creating and Configuring a BIND DNS
This section explains how to obtain and configure a DNS using Berkeley Internet Name Domain (BIND) software obtained via the Internet. If you are running Windows NT 4.0, you can use the Microsoft DNS Server option to create a DNS instead of downloading and configuring the BIND software.
The DNS master server is the domain name database server that you constantly access.
You may also want a DNS secondary, or slave, server that you can use in the event your master DNS service malfunctions. The slave begins operating as soon as any problem with the DNS master is detected. This prevents downtime. These procedures explain how to create and configure the master DNS only.
To Obtain BIND Freeware
1. Access your Internet browser. Go to the Software.com home page.
2. Locate the Free Software button.
Note: The Software.com home page may change in appearance. If you do not see a Free Software button, you will have to locate the button or link that enables you to download the BIND freeware.
3. Select BIND for NT. Download it onto your hard drive.
The self-extracting zip file, Intel-bind###.exe (### represents the release numbers) is placed in a directory that you specify.
4. Run Intel-bind###.exe by double clicking on the filename in File Manager or Explorer, or by using the File Run menu command.
The WinZip Self-Extractor dialog box appears with a default installation directory displayed. If you do not want to install to the default directory, enter the desired directory name.
5. Choose Unzip. The file is unzipped. By default, during the unzip process, a Temp directory and Bindinst subdirectory are created on your boot drive.
The following message appears:
12 files unzipped successfully.
Note: If the message does not display, the software was not downloaded and/or unzipped correctly. Repeat the process before continuing.
6. Click OK, Close.
Using BIND to Create Your DNS Service
1. From File Manager or Windows Explorer, locate and open the directory \Temp\BINDINST on your boot drive.
2. Run Setup.exe. The Domain Name Service Setup window appears. A Readme.txt file displays. After reading the file, close it. Setup will not continue while the Readme.txt file is open.
3. Follow the prompts. You are prompted to enter the user's name for BIND. Enter:
System
as the user of the BIND DNS server.
4. You are then prompted to enter the Internet domain name, or if you are using a subnet, to enter the subnet name. Enter the Internet domain name or subnet. For example,
banyan.com
Your machine's host name is then displayed.
5. Click OK to accept it, or if it is incorrect, follow the instructions in the dialog box to change the host name.
6. You are prompted to enter the network ID. Enter the network ID. For example, if your IP address is 128.45.67.89, enter 128.45
7. You are prompted to enter the subnet wildcard or mask if desired.
- If you are not using a subnet wildcard or mask, click Next.
- If you are entering a subnet mask or wildcard, do so, then click Next.
8. The default directory location for storing the DNS information is displayed.
For example:
C:\Win32app\BIND
- To accept the default location, choose Next.
- To specify another location, choose Browse and then select another location.
The Select Components dialog box appears.
9. Select Primary DNS.
You are prompted as to whether you want to see the configuration files that were created during the setup process.
10. Choose Yes to verify that all the necessary configuration files are created.
Close each file after it displays. The configuration files are
Named.boot
db.127.0.0
db.zoneinfo
db.inaddr11. You are prompted as to whether you want to insert the IP Address of the DNS you are using in your TCP/IP DNS search list. (You are adding your own IP address to the DNS search table.) Click Yes.
Note: In step 11, you are entering your own IP address in the DNS table. The IP address is also added to the Windows NT network configuration settings.
The following message appears:
"Setup is complete. The BIND service is running."
12. You are prompted as to whether you want to view the BIND documentation. Click Yes or No according to what you want to do.
13. To complete the process follow the instructions in "Stopping the BIND Service", "Editing db.inaddr", "Editing db.zoneinfo" and "Editing named.boot."
You must also edit the configuration files that were created as part of your DNS setup, but before you do so, you need to stop the BIND service.
1. From your Windows NT desktop, open the Control Panel.
2. Select DNS Controller.
On the Domain Name Server dialog box, the selected radio button is DNS Server is currently Running
3. Choose Stop Server. The following message appears:
Name Server Stopped.
4. Click OK.
The configuration file db.inaddr is the reverse lookup file, that is, you can use the IP address to find the symbolic host name. Before editing this file, be sure to stop the BIND service. For instructions, see "Stopping the BIND Service" above.
In this procedure you will need to enter specific portions of the IP address.
1. Using Notepad or another DOS editor, open the db.inaddr file.
2. At the end of the file, locate the section labeled "Addresses point to canonical name." (The canonical name is the "official" domain name.) There are several sample entries.
3. On the line beneath the last sample entry, before the semicolon (;) at the beginning of the line, enter:
- host ID.subnet ID
- IN PTR
- host name.domain name.(with trailing dot)
For example,
89.67 IN PTR Server-one.Banyan.com.
- where 89 is the host ID and 67 is the subnet ID
- the uppercase string IN PTR
- Server-one is the host name
- Banyan.com. is the domain name followed by a trailing dot (.). The trailing dot indicates the end of the fully-qualified domain name.
4. Save and Exit.
Before editing this file, be sure to stop the BIND service.
1. Using Notepad or another DOS editor, open the configuration file, db.zoneinfo.
2. Locate the section labeled "Define local hosts". There are several sample entries.
3. On the line beneath the last sample entry, before the semicolon (;) at the beginning of the line, enter
- host name
- IN A (all uppercase)
- IP address
For example,
server-one IN A 128.45.67.89
- where server-name is the host name
- the uppercase string IN A
- the IP address 128.45.67.89
4. Save and Exit.
To allow for reverse address-to-host mapping, be sure to edit the named.boot file. Before editing this file, be sure to stop the BIND service.
1. Using Notepad or another DOS editor, open the file Named.boot.
2. Near the end of the file, locate a line that begins with ";primary."
3. On the next line, remove the semicolon (;) and enter:
- primary
- the network ID entered in reverse. For example, if 128.45 is your network ID, enter 45.128
- the following string exactly as it appears in-addr.arpa named.inaddr
The entire entry should resemble the following:
primary 45.128.in-addr.arpa named.inaddr
- the string primary
- the reverse network ID 45.128 with a trailing dot (.)
- the string in-addr.arpa named.inaddr
4. Save and Exit.
Creating a DNS Using Microsoft DNS Server
If you are running Windows NT 4.0, you can use the Microsoft DNS Server option to create a DNS instead of downloading and configuring the BIND software.
1. From Windows NT 4.0 Control Panel, select Network.
2. From the Network window, choose the Services tab.
3. On the services window, click Add. The Select Network Service dialog box appears.
4. Choose Microsoft DNS Server and click OK. The Windows NT Setup dialog box prompts you to select or verify the default location of Windows NT files.
Enter a different file location if necessary.
5. Click Continue. The files are copied.
When the process is complete, the Microsoft DNS Server entry appears on the Service window.
6. Click OK.
Configuring a Windows NT 4.0 DNS Server
1. On your Windows NT server, from Programs, Administrative Tools, run DNS Manager.
2. Right-click on ServerList and select New Server on the shortcut menu. The Add DNS Server dialog box appears.
3. Enter one of the following in the DNS Server field:
- host name - if you want to do your DNS lookups by host name
- IP address - if you want to do your DNS lookups by IP address
4. Click OK.
5. To create a primary zone, right-click on the host name or IP address that you just entered and select New Zone on the shortcut menu. The Creating New Zone dialog box appears.
6. Choose Primary as the zone type and click Next.
7. Enter the domain name in the Zone Name field.
8. Tab to the Zone File field to automatically create the zone file and click Next.
If you want to use WINS with DNS
- Right-click Zone and select Properties on the shortcut menu.
- Click on the WINS Lookup tab.
- Select the Use WINS Resolution checkbox.
- Enter the WINS IP Address in the WINS Servers field and click Add, OK.
9. Click Finish.
To Add the Reverse Address Resolution
1. Right-click on the host name or IP address that you just entered and select New Zone on the shortcut menu. The Creating New Zone dialog box appears.
2. Choose Primary as the zone type and click Next.
3. Enter the following:
- the reverse of the network ID you previously entered followed by a trailing dot. For example, if you previously entered 128.45 as your network ID, enter 45.128.
- the string in-addr.arpa 45.128.in-addr.arpa
- where 45.128. is the reverse network ID with a trailing dot
- the string in-addr.arpa
4. Tab to the Zone File field to create the zone file and click Next.
If you are Using WINS with DNS
- Right-click Zone and select Properties on the shortcut menu.
- Click on the WINS Reverse Lookup tab.
- Select the Use WINS Resolution checkbox.
- Enter the host domain name. Click OK.
5. Click Finish.
To Add a New Host to a Primary Zone
1. Right-click on primary domain name and select New Host on the shortcut menu.
2. Enter the host name.
3. Tab to the IP Address field and enter the IP Address.
4. Click Create Associate PTR Record.
5. Click Add Host. Continue adding hosts as necessary. (The PTR record maps an IP address to a host name in a DNS reverse zone, that is, IN- addr.arpa DNS domain.)
6. When you have entered all the hosts, click Done.
7. On the DNS menu, select Exit.
