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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd"><HTML><HEAD><TITLE>Josh's Linux Guide - Setting Up a Nameserver</TITLE> <META NAME="Description" CONTENT="Instructions on installing and configuring BIND 8."></HEAD><LINK REL="stylesheet" TYPE="text/css" HREF="default.css"><BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#7F007F"><H2><A NAME="0">Setting Up a Nameserver</A></H2><FONT SIZE="-1"><B>Created on July 24, 1998</B></FONT><BR><FONT SIZE="-1"><B>Last updated: October 20, 1999</B></FONT><BR><FONT SIZE="-1"><B>Development stage: Alpha</B></FONT><BR><P>A nameserver is a server that resolves hostnames to IP addresses.Instead of having to type in "209.81.10.250", I can just type in"www.penguincomputing.com" to get to a site. <AHREF="http://www.isc.org/bind.html" TARGET="_top">BIND</A> is nameserversoftware that runs on many types of machines, originally written by PaulVixie and now maintained by the <A HREF="http://www.isc.org/"TARGET="_top">Internet Software Consortium (ISC)</A>.</P><P>This was one of the trickiest things I've had to try to figure out sofar. I didn't talk to anybody as to how to go about this, unlike PPPsetup. But I finally found the Linux DNS HOWTO and used that. Hopefullythis will save you some trouble. Here I have instructions for BIND 8,which is newer and more advanced than BIND 4 (which some distributionsstill use).</P><OL><LI><A HREF="#remove">Removing Old Nameserver (BIND 4)</A><LI><A HREF="#install">Installing New Nameserver (BIND 8)</A><LI><A HREF="#config">Configuration: /etc/named.conf</A><LI><A HREF="#cache">Caching Nameserver</A><LI><A HREF="#zones">Zone Files in /var/named</A><LI><A HREF="#examples">Examples of Zone Files</A> <UL> <LI><A HREF="#domains">Domains</A> <LI><A HREF="localhost">Localhost</A> <LI><A HREF="#reverse">Reverse Mapping</A> </UL><LI><A HREF="#resources">Resources</A></OL><A NAME="remove"></A><H3><A NAME="1">Removing Old Nameserver (BIND 4)</A></H3><P>In the event that your distribution already comes with BIND 8, then allyou need to do is find out how the configuration works, and/or put inentries for machines that the Linux box will be the nameserver for. Ithink Slackware comes with BIND 8. I don't know about Debian. Most newdistributions (including Red Hat 5.2) will already have BIND 8 so you'llprobably have to look for the configuration file and how it has beenpre-configured.</P><P>I had to remove the old nameserver first, so it wouldn't get in the wayof the new one. It's fine to remove it and replace it with a new one;there aren't any other packages that <I>really</I> depend on it.</P><P>Using Red Hat 5.1, I typed <B><TT>rpm -e bind bind-utilscaching-nameserver</TT></B>. That removed all the old packages. Be carefulabout this, especially about bind-utils, because bind-utils contains thetools such as <B>dnsquery</B> and <B>nslookup</B> that you might be usingfairly often. Red Hat 5.2 already has BIND 8.</P><A NAME="install"></A><H3><A NAME="2">Installing New Nameserver (BIND 8)</A></H3><P>First, download BIND from <AHREF="ftp://ftp.isc.org/">ftp.isc.org</A></TT>. If you've got it on yoursystem already, then you don't need to get BIND 8 unless you want to makea minor upgrade. The filename is something like bind-8.1.2-src.tar.gz,which says that it's BIND version 8.1.2 in source format (which you haveto compile on your system). I'll work with the source version since that'swhat I usually do anyway.</P><P>After you have it on your system, type <B><TT>tar -zxvfbind-8.1.2.tar.gz</TT></B>. It will extract a directory called<TT>src/</TT> and that's where you go into. Simply type "make"and have it compiled for you. If you need anything to be tweaked then readthe INSTALL file (<B><TT>less INSTALL</TT></B>) and find what you need.After it finishes compiling, type <B><TT>make install</TT></B>.</P><A NAME="config"></A><H3><A NAME="3">Configuration: /etc/named.conf</A></H3><P>Configuring the nameserver was probably the hardest part of the processthat I had to go through. Hopefully, what I've written up about what Ilearned will save the reader some trouble.</P><P>The main BIND 8 configuration file is in <TT>/etc/named.conf</TT>. Theconfiguration syntax for the file is documented at <AHREF="http://www.isc.org/bind8/config.html" TARGET="_top">http://www.isc.org/bind8/config.html</A>. Here's a sample ofa configuration file (as /etc/named.conf), with an explanation below.</P><PRE>/* * A simple BIND 8 configuration */options { directory "/var/named";};zone "penguincomputing.com" in { type master; file "master/penguincomputing.com";};zone "0.0.127.in-addr.arpa" in { type master; file "zone/127.0.0";};zone "." in { type hint; file "named.cache";};</PRE><P>In "options" I only had one option: where the directory for<B>zone files</B> were. Zone files are where information about domains isstored, and each file has information about a zone. It's a section tocover, I guess, so that's why they're called zones. I have<TT>/var/named/</TT> as my named data directory.</P><P>The "penguincomputing.com" section is pretty straightforward.It just indicates the location of the penguincomputing.com zone files andtells <B>named</B> that this server is a master nameserver for thepenguincomputing.com zone.</P><P>The "0.0.127.in-addr.arpa" zone is for mapping localhost to127.0.0.1, basically. It has its own zone file.</P><P>The "." zone indicates a caching nameserver; that is, someonecan actually use your machine to resolve hostnames (including you). I'veheard that is is efficient especially when using PPP connections, but Idon't know for sure. Read the "Caching Nameserver" section toread up on how to create one.</P><A NAME="cache"></A><H3><A NAME="4">Caching Nameserver</A></H3><P>First you need to get a "named.cache" file. I'm not sure ifyou can name it anything else, but let's just use that filename. In/var/named/ (or wherever you put your nameserver's data files), type<B><TT>dig @a.root-servers.net > named.cache</TT></B>. This will ask forthe addresses of the main DNS servers of the Internet and direct them to afile. I'm <I>guessing</I> that the purpose of this is to give your machinean idea of which machines on the Internet to ask about hosts.</P><P>Periodically, like once a month, update the named.cache file by runningthat command once in a while. You can use a cron job for that. If youdon't know what I'm talking about here, don't worry about it. Just be sureto update it using <B>dig</B> once in a while, that's all you have todo.</P><P>You have <TT>/etc/named.conf</TT> point to wherever your named.cachefile is under the "." zone.</P><A NAME="zones"></A><H3><A NAME="5">Zone Files in /var/named/</A></H3><P>In <TT>/var/named/</TT>, I created directories for every type of zone Ihad. The directories I have in there are: <TT>master</TT>,<TT>slave/</TT>, and <TT>zone</TT>. With the domain name system, there isa server for each domain that is the main server (the master). I supposethat the slave server is there in case the main (master) server is down.For each domain there should be <I>at least</I> 2 servers, one master andone slave. That's just the way it goes.</P><P>While interning at <A HREF="http://www.penguincomputing.com/" TARGET="_top">Penguin Computing</A> I set up both the master and slave DNSservers. The master's information should go in the <TT>master</TT>directory. You should be able to figure out where the slave's informationgoes. The information they store is the same, but since one machine is themain one that keeps the information (master) and the other simply followsthe master's information (slave), you need to stay organized and make sureyou're configuring the right machine for its right place in the nameserversystem.</P><P>Note that the slave nameserver for one domain can also be the masternameserver for another domain. There just can't be two masters for asingle domain, though I think there can be several slaves.</P><A NAME="examples"></A><H3><A NAME="6">Examples of Zone Files</A></H3><P>To figure something like this out, I was looking hard for examples. Andexamples really help, so hopefully you won't be too confused by myexamples. Hey, I try.</P><A NAME="domains"></A><H4><A NAME="7">Domains</A></H4><P>The information for each domain is put in a single file. This filecontains valuable information for each domain, such as machines that are⌨️ 快捷键说明
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