Linuxcare: How To Set Up DNS Services: 3 Part Series

Name resolution is the process by which hostnames are converted to IP addresses. It is what allows users to contact a host with a name, such as www.yahoo.com, rather than with 204.71.200.67. There are several mechanisms by which such name to IP address translation can occur. Most Linux users are familiar with the use of the /etc/hosts file to perform name resolution. While this method is simple and straightforward, it's use is only suitable in home networks and small local area networks. The reason for this is that this method of name resolution is not scalable. On a LAN with hundreds of hosts, the addition or removal of hosts on the network would require the /etc/hosts file to be updated on every host on the network. While this can be made less painful with the use of rsync or NIS, it would still be fairly painful.

Fortunately, an alternative exists. A much better solution is to setup a DNS server for your network. Once a DNS server is in place, the machines on the network would not have to perform name resolution themselves. Instead, they send a name resolution query to the DNS server. The DNS server will perform the name resolution and respond with the IP address for the hostname queried.

Sounds great, but how difficult is it? It is not hard at all to setup a simple DNS server for your LAN. For demonstration purposes, I will be referring to the imaginary 192.168.1.0 network below, using the domain name, gracie.edu.

We are going to set up helio as the DNS server for my domain using Red Hat 6.1. To configure helio as the DNS server, we have to first make sure that the software necessary to provide the DNS service is installed. This software is the Berkeley Internet Name Domain software, more commonly known as BIND. To install the BIND software from a Red Hat installation CD, run the following command from the directory on the CD containing the rpm:

<# rpm -ivh bind-8.2.1-7.i386.rpm>
<# rpm -ivh bind-devel-8.2.1-7.i386.rpm>
<# rpm -ivh bind-utils-8.2.1-7.i386.rpm>
<# rpm -ivh caching-nameserver-6.0-2.noarch.rpm>

Once the BIND rpm packages are installed, we can begin our configuration. BIND is a client/server program.

Come back next week when we will discuss the server configuration portion. We will configure named, create a zone file, set up a zone statement, and a reverse zone statement.

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Chen Chang is a Linuxcare University Courseware Writer. His areas of interest include TCP/IP networking, Samba, open source advocacy, and system administration. His "Power Tips" column appears every Monday at linux.com. Send your questions and comments to cchang@linuxcare.com.