How to Install and Configure DNS Server in CentOS
To install and configure DNS server in CentOS
A Domain Name System is a service which is used for translating the human readable domain name into a machine readable IP address. The DNS server stores all the corresponding IP addresses and facilitates the transfer of the requested IP addresses to the user.
To set up Primary DNS server
In this tutorial we have two minimal servers of CentOS 6, one is primary DNS server and the other is secondary DNS server. A Cent0S 6 desktop is used for the client configuration.
The first and foremost step to setup the Primary DNS server is to install and bind the package with the following command.
[root@primarydns ~]# yum install -y bind*
Loaded plugins: fastestmirror
Setting up Install Process
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Installed:
bind.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-chroot.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-devel.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-dyndb-ldap.x86_64 0:2.3-8.el6
bind-libs.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-sdb.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-utils.x86_64 32:9.8.2-0.47.rc1.el6_8.2
Dependency Installed:
portreserve.x86_64 0:0.0.4-11.el6 postgresql-libs.x86_64 0:8.4.20-6.el6
Complete!
Now edit the name server configuration file as follows.
[root@primarydns ~]# vi /etc/named.conf
In that file add primary DNS server IP in listen on port 53 option. Enter IP range of hosts in the allow-query option. Add secondary DNS server IP in allow-transfer option.
Configure the named.conf file by adding the following line in it.
Dnssec-lookaside auto
The next step is to define the forward and reverse lookup zone for the Primary DNS server by making the following changes.
zone" linuxhelp1.local" IN {
type master
file " forward.linuxhelp1"
allow-update { none }
}
zone" 7.168.192.in-addr.arpa" IN {
type master
file " reverse.linuxhelp1"
allow-update { none }
}
Now create forward zone file with the following command and then add the below mentioned lines accordingly.
[root@primarydns ~]# vi /var/named/forward.linuxhelp1
$TTL 86400
@ IN SOA primarydns.linuxhelp1.local. root.linuxhelp1.local. (
2014051001 serial
3600 refresh
1800 retry
604800 expire
86400 minimum
)
@ IN NS primarydns.linuxhelp1.local.
@ IN NS secondarydns.linuxhelp1.local.
@ IN A 192.168.7.222
@ IN A 192.168.7.223
@ IN A 192.168.7.235
primarydns IN A 192.168.7.222
secondarydns IN A 192.168.7.223
client IN A 192.168.7.235
Once the above changes are made to the forward zone file, use the following command to create a reverse zone file. Add to it the lines given below the command.
[root@primarydns ~]# vi /var/named/reverse.linuxhelp1
$TTL 86400
@ IN SOA primarydns.linuxhelp1.local. root.linuxhelp1.local. (
2014051001 serial
3600 refresh
1800 retry
604800 expire
86400 minimum
)
@ IN NS primarydns.linuxhelp1.local.
@ IN NS secondarydns.linuxhelp1.local.
@ IN PTR linuxhelp1.local.
primarydns IN A 192.168.7.222
secondarydns IN A 192.168.7.223
client IN A 192.168.7.235
222 IN PTR primarydns.linuxhelp1.local.
223 IN PTR secondarydns.linuxhelp1.local.
235 IN PTR client.linuxhelp1.local.
Change group ownership for the two files that are created with the following command.
[root@primarydns ~]# chgrp named /var/named/forward.linuxhelp1
[root@primarydns ~]# chgrp named /var/named/reverse.linuxhelp1
If you want to check for the errors in the conf and zone files, use the following commands.
[root@primarydns ~]# named-checkconf /etc/named.conf [root@primarydns ~]# named-checkzone linuxhelp1.local /var/named/forward.linuxhelp1 Zone linuxhelp1.local/IN: loaded serial 2014051001 OK [root@primarydns ~]# named-checkzone 7.168.192.in-addr.arpa /var/named/reverse.linuxhelp1 Zone linuxhelp1.local/IN: loaded serial 2014051001 OK
Start the DNS service with the following command.
[root@secondarydns ~]# service named start
Generating /etc/rndc.key: [ OK ]
Starting named: [ OK ]
You can run the following command to start the DNS service at boot.
[root@secondarydns ~]#chkconfig named on
Add the following rules to the /etc/sysconfig/iptables file so that you can configure the iptables rules.
-A INPUT -i lo -j ACCEPT -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 53 -j ACCEPT -A INPUT -p udp -m state --state NEW -m udp --dport 53 -j ACCEPT -A INPUT -j DROP
The above lines should be added in between the OUTPUT ACCEPT and COMMIT.
Use the following command to save the iptables rules.
[root@primarydns named]# service iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ]
The next step is to edit the resolv.conf file by adding the below mentioned Nameservers to it.
Search linuxhelp1.local Nameserver 192.168.7.222 Nameserver 192.168.7.223
Invoke the dig command to check the DNS server
[root@primarydns named]# dig primarydns.linuxhelp1.local
< < > > DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6_8.2 < < > > primarydns.linuxhelp1.local
global options: +cmd
Got answer:
-> > HEADER<
You can check for the available hosts in the DNS with the following command.
[root@primarydns named]# nslookup linuxhelp1.local
Server: 192.168.7.222
Address: 192.168.7.222#53
Name: linuxhelp1.local
Address: 192.168.7.235
Name: linuxhelp1.local
Address: 192.168.7.222
Name: linuxhelp1.local
Address: 192.168.7.223
To setup secondary dns server
To set up the secondary DNS, you have to install the bind package as follows.
[root@primarydns ~]# yum install -y bind*
Loaded plugins: fastestmirror
Setting up Install Process
&hellip
&hellip
&hellip
Installed:
bind.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-chroot.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-devel.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-dyndb-ldap.x86_64 0:2.3-8.el6
bind-libs.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-sdb.x86_64 32:9.8.2-0.47.rc1.el6_8.2 bind-utils.x86_64 32:9.8.2-0.47.rc1.el6_8.2
Dependency Installed:
portreserve.x86_64 0:0.0.4-11.el6 postgresql-libs.x86_64 0:8.4.20-6.el6
Complete!
Now edit the named.conf file by adding the secondary DNS server IP to the listen on port 53 option, and then define the IP range for the hosts in the allow-query option. After it is done, add the following line into the conf file.
Dnssec-lookaside auto
Once it is done, define forward and reverse lookup zone for the secondary DNS server as follows.
zone" linuxhelp1.local" IN {
type slave
file " slaves/linuxhelp1.fwd"
masters { 192.168.7.222 }
}
zone" 7.168.192.in-addr.arpa" IN {
type slave
file " slaves/linuxhelp1.rev"
masters { 192.168.7.222 }
}
Start the named service with the following command.
[root@secondarydns ~]# service named start
Generating /etc/rndc.key: [ OK ]
Starting named: [ OK ]
You can start the DNS service at boot with the following command.
[root@secondarydns ~]#chkconfig named on
Invoke the following command to list the file in the secondary DNS server.
It isn' t required to create a zone file here as it will be resolved from Master Server when the Named Service is started.
[root@secondarydns ~]# ls -l /var/named/slaves/
total 8
-rw-r--r-- 1 named named 508 Oct 25 06:10 linuxhelp1.fwd
-rw-r--r-- 1 named named 603 Oct 25 06:11 linuxhelp1.rev
Use the following command to view the forward file.
[root@secondarydns ~]# cat /var/named/slaves/linuxhelp1.fwd
$ORIGIN .
$TTL 86400 1 day
linuxhelp1.local IN SOA primarydns.linuxhelp1.local. root.linuxhelp1.local. (
0 serial
86400 refresh (1 day)
3600 retry (1 hour)
604800 expire (1 week)
10800 minimum (3 hours)
)
NS primarydns.linuxhelp1.local.
NS secondarydns.linuxhelp1.local.
A 192.168.7.222
A 192.168.7.223
A 192.168.7.235
$ORIGIN linuxhelp1.local.
client A 192.168.7.235
primarydns A 192.168.7.222
secondarydns A 192.168.7.223
In case you want to see the reverse file, use the following command.
[root@secondarydns ~]# cat /var/named/slaves/linuxhelp1.rev
$ORIGIN .
$TTL 86400 1 day
7.168.192.in-addr.arpa IN SOA primarydns.linuxhelp1.local. root.linuxhelp1.local. (
0 serial
86400 refresh (1 day)
3600 retry (1 hour)
604800 expire (1 week)
10800 minimum (3 hours)
)
NS primarydns.linuxhelp1.local.
NS secondarydns.linuxhelp1.local.
PTR linuxhelp1.local.
$ORIGIN 7.168.192.in-addr.arpa.
222 PTR primarydns.linuxhelp1.local.
223 PTR secondarydns.linuxhelp1.local.
235 PTR client.linuxhelp1.local.
client A 192.168.7.235
primarydns A 192.168.7.222
secondarydns A 192.168.7.223
You can setup the client machine by invoking the following command.
Set the DNS server for the client machine using setup command.
[root@localhost Desktop]# hostname
Localhost.localdomain
Now restart the network and check the Hostname.
[root@localhost Desktop]# hostname
Client.linuxhelp1.local
You can now see the host name assigned from the DNS server.
Error: bind97-libs conflicts with bind-libs
Error: bind97-devel conflicts with bind-libbind-devel
Error: bind97-chroot conflicts with bind-chroot
Error: bind97-utils conflicts with bind-utils
Do you think I need to run my own Name servers?
can you please explain the other dns zones like stub zone
can we configure the stubzone in linux?