How to Setup Caching NameServer on CentOS/RHEL 6/5

    RahulBy 2 Mins Read

    Definition at Wikipedia:

    Caching name servers, also called DNS caches, store DNS query results for a period of time determined in the configuration (time-to-live) of each domain-name record. DNS caches improve the efficiency of the DNS by reducing DNS traffic across the Internet, and by reducing load on authoritative name-servers, particularly root name-servers. Because they can answer questions more quickly, they also increase the performance of end-user applications that use the DNS. Read more

    This article will help you to setup caching nameserver on your CentOS/RHEL 6 system.

    Step 1: Install BIND Packages

    Install bind packages using below command. In CentOS/RHEL 6 chaching-nameserver package has been included with bind package.

    # yum install bind bind-chroot

    Step 2: Create Configuration File

    Copy bind configuration file from bind sample files using below command. Change the path of files as per version you have installed.

    # cd /var/named/chroot/etc
# cp /usr/share/doc/bind-9.9.2/sample/etc/named.conf  .
# cp /usr/share/doc/bind-9.9.2/sample/etc/named.rfc1912.zones  .

    Step 3: Update Configuration File

    Edit bind configuration file in your favorite editor and make necessary changes as per below settings or use below configuration.

    # /var/named/chroot/etc/named.conf

    // /var/named/chroot/etc/named.conf
options {
        listen-on port 53 { 127.0.0.1; any; };
        listen-on-v6 port 53 { ::1; };
        directory       "/var/named";
        dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
        allow-query     { localhost; any; };
        allow-query-cache    { localhost; any; };
        recursion yes;

        dnssec-enable yes;
        dnssec-validation yes;
        dnssec-lookaside auto;

        /* Path to ISC DLV key */
        bindkeys-file "/etc/named.iscdlv.key";

        managed-keys-directory "/var/named/dynamic";
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

include "/etc/named.rfc1912.zones";

    Now update required permissions on configuration files using below command.

    # chown root:named named.conf named.rfc1912.zones

    Step 4: Check Configuration File

    We recommend to check DNS configuration file before restarting service.

    # named-checkconf named.conf

    Step 5: Restart Bind Service

    Now installation of bind service has been completed. Lets start bind (named) service using following command.

    # service named restart

    Enable auto start bind service on system boot.

    # chkconfig named on

    Step 6: Finally Test Caching Only DNS

    Send query to your dns server directly using below command.

    Syntax: nslookup <domainname> <caching dns server name/ip>

    # nslookup yahoo.com 192.168.1.90

    [Sample Output:]

    Server:         192.168.1.91
Address:        192.168.1.91#53

Non-authoritative answer:
Name:   yahoo.com
Address: 98.138.253.109
Name:   yahoo.com
Address: 98.139.183.24
Name:   yahoo.com
Address: 206.190.36.45

    Congratulation’s! You have successfully configured caching nameserver on your linux system. Read out next articles Configure DNS Server on CentOS/RHE 6 and Setup Master Slave DNS Server on CentOS/RHEL 6.

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    7 Comments

    1. khalilamar on

      Hello again

      from the /var/log/messages
      I can read the following line: Oct 29 03:06:36 ns named[960]: loading configuration from ‘/etc/named.conf’
      Which means, the /var/named/chroot/etc/named.conf has no relationship with /etc/named.conf

      When I compare both files, I see some differences.
      [[email protected] etc]# diff -y /etc/named.conf /var/named/chroot/etc/named.conf
      // <
      // named.conf <
      // <
      // Provided by Red Hat bind package to configure the ISC BIND <
      // server as a caching only nameserver (as a localhost DNS re <
      // <
      // See /usr/share/doc/bind*/sample/ for example named configu <
      // <
      dnssec-lookaside auto;

      /* Path to ISC DLV key */ | /* Path to ISC DLV key */
      bindkeys-file “/etc/named.iscdlv.key”; | bindkeys-file “/etc/named.iscdlv.key”;

      managed-keys-directory “/var/named/dynamic”; | managed-keys-directory “/var/named/dynamic”;
      }; };

      logging { logging {
      channel default_debug { channel default_debug {
      file “data/named.run”; file “data/named.run”;
      severity dynamic; severity dynamic;
      }; };
      }; };

      zone “.” IN { <
      type hint; <
      file "named.ca"; <
      }; <
      <
      include "/etc/named.rfc1912.zones"; include "/etc/named.rfc1912.zones";
      include "/etc/named.root.key"; <

      [[email protected] etc]#

      And…
      from http://www.howtoforge.com/perfect-server-centos-5.6-x86_64-ispconfig-3-p5
      Can you explain why did this guy do the following ?

      chmod 755 /var/named/
      chmod 775 /var/named/chroot/
      chmod 775 /var/named/chroot/var/
      chmod 775 /var/named/chroot/var/named/
      chmod 775 /var/named/chroot/var/run/
      chmod 777 /var/named/chroot/var/run/named/
      cd /var/named/chroot/var/named/
      ln -s ../../ chroot
      touch /var/named/chroot/var/named/named.local
      cp /usr/share/doc/bind-9.3.6/sample/var/named/named.root /var/named/chroot/var/named/named.root
      touch /var/named/chroot/etc/named.conf.local
      vi /var/named/chroot/etc/named.conf

      //
      // named.conf
      //
      // Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
      // server as a caching only nameserver (as a localhost DNS resolver only).
      //
      // See /usr/share/doc/bind*/sample/ for example named configuration files.
      //
      options {
      listen-on port 53 { any; };
      listen-on-v6 port 53 { any; };
      directory "/var/named/chroot/var/named";
      dump-file "/var/named/chroot/var/named/data/cache_dump.db";
      statistics-file "/var/named/chroot/var/named/data/named_stats.txt";
      memstatistics-file "/var/named/chroot/var/named/data/named_mem_stats.txt";
      allow-query { any; };
      recursion no;
      allow-recursion { none; };
      };
      logging {
      channel default_debug {
      file "data/named.run";
      severity dynamic;
      };
      };
      zone "." IN {
      type hint;
      file "named.root";
      };
      include "/var/named/chroot/var/named/named.local";

      Reply
    2. khalilamar on

      You need to add: yum install bind-utils
      for those that are following your instructions right after a clean install from CentOS minimal.
      Thanks

      Reply
    3. Bill Carlson on

      Isn’t there any other option or package to use for a dns cache?

      For me and many, BIND is specifically a very poor piece of software and wish to avoid.

      Debian has several variants, I don’t understand why Redhat Enterprise would not have a good robust alternative.

      Reply
    5. Burak on

      Hi,

      Using yum install and update named I have bind.x86_64 version 30:9.3.6-20.P1.el5_8.6 installed on Centos 5.5 64bit.
      It is working and running. However, I suspect that it does not do caching.
      So I tried to use some lines from your configuration.
      When I run, named displayed following errors:
      unknown option ‘allow-query’
      unknown option ‘allow-query-cache’
      unknown option ‘recursion’
      unknown option ‘dnssec-enable’
      unknown option ‘dnssec-validation’
      unknown option ‘dnssec-lookaside’

      What could be the reason, is centos 5 too old?

      Reply
    6. Adrian on

      Hello! first of all thanks for taking the time to read my query …

      Know where cahe record is saved?
      is to find the sites visited by my office terminals and generate blocking rules for certain domains.

      thank you very much!

      Adrian!

      pd: sorry for my bad English

      Reply

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