HOW DO I CONFIGURE DNS SERVER IN LINUX 6



Here Im Using RHEL Server to Setup the DNS Server using BIND
[root@masterdns ~]# lsb_release -a
LSB Version:    :core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch
Distributor ID: RedHatEnterpriseServer
Description:    Red Hat Enterprise Linux Server release 6.2 (Santiago)
Release:    6.2
Codename:   Santiago
Primary DNS Server (or) Master DNS Server:
IP Address :    192.168.0.200
Hostname   :    masterdns.linuxzadmin.local
Secondary DNS Server (or) Slave DNS Server:
IP Address :    192.168.0.201
Hostname   :    slavedns.linuxzadmin.local
Nodes Machines :
IP Address :    192.168.0.205  ## Hostname : node1.linuxzadmin.local
IP Address :    192.168.0.206  ## Hostname : node2.linuxzadmin.local
IP Address :    192.168.0.207  ## Hostname : node3.linuxzadmin.local
IP Address :    192.168.0.208  ## Hostname : node4.linuxzadmin.local
1.    Primary DNS Server (or) Master DNS Server :
[root@masterdns ~]# yum install bind* -y
1.    Then Edit the Configuration of name server
[root@masterdns ~]# vim /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 { 127.0.0.1; 192.168.0.200; }; # Master DNS Servers IP
    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; 192.168.0.0/24; }; # IP Range of Hosts
    allow-transfer  { localhost; 192.168.0.201; }; # Slave DNS Servers IP
    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;
        };
};

zone "." IN {
    type hint;
    file "named.ca";
};
zone"linuxzadmin.local" IN {
type master;
file "forward.linuxzadmin";
allow-update { none; };
};
zone"0.168.192.in-addr.arpa" IN {
type master;
file "reverse.linuxzadmin";
allow-update { none; };
};
include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";
Save and Exit the named.conf using wq!
1.    Creat the Forward and Reserve Zone files as mentioned in named.conf
FORWARD ZONE :

a.) Create a Forward Zone file under /var/named in the name of forward.linuxzadmin
There are Sample files under the /var/named/ Directory, Just make a Copy of that file and modify it as our need
b.) Make a Copy of sample file as below
[root@masterdns ~]# cp /var/named/named.localhost /var/named/forward.linuxzadmin
c.) Edit the file forward.linuxzadmin
[root@masterdns ~]# vim /var/named/forward.linuxzadmin


$TTL 86400
@       IN SOA  masterdns.linuxzadmin.local. root.linuxzadmin.local. (
                                2014051001      ; serial
                                        3600    ; refresh
                                        1800    ; retry
                                        604800  ; expire
                                        86400   ; minimum
)
@               IN      NS      masterdns.linuxzadmin.local.
@               IN      NS      slavedns.linuxzadmin.local.
@               IN      A       192.168.0.200
@               IN      A       192.168.0.201
@               IN      A       192.168.0.205
@               IN      A       192.168.0.206
@               IN      A       192.168.0.207
@               IN      A       192.168.0.208
masterdns       IN      A       192.168.0.200
slavedns        IN      A       192.168.0.201
node1           IN      A       192.168.0.205
node2           IN      A       192.168.0.206
node3           IN      A       192.168.0.207
node4           IN      A       192.168.0.208
RESERVE ZONE:

a.) Create a Reserver Zone file under /var/named in the name of reverse.linuxzadmin
There are Sample files under the /var/named/ Directory, Just make a Copy of that file and modify it as our need
b.) Make a Copy of sample file as below
[root@masterdns ~]# cp /var/named/named.loopback /var/named/reverse.linuxzadmin

c.) Edit the file reverse.linuxzadmin
[root@masterdns ~]# vim /var/named/reverse.linuxzadmin


$TTL 86400
@       IN SOA  masterdns.linuxzadmin.local. root.linuxzadmin.local. (
                                2014051001      ; serial
                                        3600    ; refresh
                                        1800    ; retry
                                        604800  ; expire
                                        86400   ; minimum
)
@               IN      NS      masterdns.linuxzadmin.local.
@               IN      NS      slavedns.linuxzadmin.local.
@               IN      PTR     linuxzadmin.local.
masterdns       IN      A       192.168.0.200
slavedns        IN      A       192.168.0.201
node1           IN      A       192.168.0.205
node2           IN      A       192.168.0.206
node3           IN      A       192.168.0.207
node4           IN      A       192.168.0.208
200             IN      PTR     masterdns.linuxzadmin.local.
201             IN      PTR     slavedns.linuxzadmin.local.
205             IN      PTR     node1.linuxzadmin.local.
206             IN      PTR     node2.linuxzadmin.local.
207             IN      PTR     node3.linuxzadmin.local.
208             IN      PTR     node4.linuxzadmin.local.
1.    The files we created was in root group We need to change those files to named group
Here we can see the files which have the root group
a.) List the files and see the permissions and group of those created zone files
[root@masterdns ~]# ls -l /var/named/
total 40
drwxr-x---. 6 root  named 4096 May 10 19:33 chroot
drwxrwx---. 2 named named 4096 Nov 16  2011 data
drwxrwx---. 2 named named 4096 Nov 16  2011 dynamic
-rw-r-----. 1 root  root   550 May 10 20:19 forward.linuxzadmin
-rw-r-----. 1 root  named 1892 Feb 18  2008 named.ca
-rw-r-----. 1 root  named  152 Dec 15  2009 named.empty
-rw-r-----. 1 root  named  152 Jun 21  2007 named.localhost
-rw-r-----. 1 root  named  168 Dec 15  2009 named.loopback
-rw-r-----. 1 root  root   676 May 10 20:35 reverse.linuxzadmin
drwxrwx---. 2 named named 4096 Nov 16  2011 slaves
b.) Change the group to named using below Command
[root@masterdns ~]# chgrp named /var/named/forward.linuxzadmin
[root@masterdns ~]# chgrp named /var/named/reverse.linuxzadmin
Here we can see the Output now which changed to named group
[root@masterdns ~]# ls -l /var/named/
total 40
drwxr-x---. 6 root  named 4096 May 10 19:33 chroot
drwxrwx---. 2 named named 4096 Nov 16  2011 data
drwxrwx---. 2 named named 4096 Nov 16  2011 dynamic
-rw-r-----. 1 root  named  550 May 10 20:19 forward.linuxzadmin
-rw-r-----. 1 root  named 1892 Feb 18  2008 named.ca
-rw-r-----. 1 root  named  152 Dec 15  2009 named.empty
-rw-r-----. 1 root  named  152 Jun 21  2007 named.localhost
-rw-r-----. 1 root  named  168 Dec 15  2009 named.loopback
-rw-r-----. 1 root  named  676 May 10 20:35 reverse.linuxzadmin
drwxrwx---. 2 named named 4096 Nov 16  2011 slaves
c.) Then we need to check the Context of the files under
[root@masterdns ~]# ls -lZd /etc/named.conf
-rw-r-----. root named system_u:object_r:named_conf_t:s0 /etc/named.conf

/etc/named.conf
/var/named/forward.linuxzadmin
/var/named/reverse.linuxzadmin
It want to be in the context of named_conf_t
If its Different than this then we need to restore the context using
# restorecon /etc/named.conf
1.    Now we need to Check for the Error in the conf file and Zone file
[root@masterdns ~]# named-checkconf /etc/named.conf

[root@masterdns ~]# named-checkzone linuxzadmin.local /var/named/forward.linuxzadmin
zone linuxzadmin.local/IN: loaded serial 2014051001
OK

[root@masterdns ~]# named-checkzone 0.168.192.in-addr.arpa /var/named/reverse.linuxzadmin
zone 0.168.192.in-addr.arpa/IN: loaded serial 2014051001
OK
1.    Start the DNS Service
[root@masterdns ~]# service named restart
Stopping named:                                            [  OK  ]

Starting named:                                            [  OK  ]

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