http://www.vivaolinux.com.br/artigo/Instalando-o-BIND-9-no-CentOS-6?pagina=2
http://ostechnix.wordpress.com/2013/01/25/setup-dns-server-step-by-step-in-centos-6-3-rhel-6-3-scientific-linux-6-3-3/
http://www.broexperts.com/2012/03/linux-dns-bind-configuration-on-centos-6-2/
http://www.isc.org/
DNS (Domain Name System) is the core component of network infrastructure. The DNS service resolves hostname into ip address and vice versa. For example if we type http://www.ostechnix.comin browser, the DNS server translates the domain name into its corresponding ip address. So it makes us easy to remember the domain names instead of its ip address.
This how-to tutorial will show you how to install and configure Primary and Secondary DNS server. The steps provided here were tested in CentOS 6.5 32 bit edition, but it should work in RHEL 6.x(x stands for version) and Scientific Linux 6.x too.
Here are my test setup scenario
Operating System : CentOS 6.5 32 bit (Minimal Server) Hostname : masterdns.ostechnix.com IP Address : 192.168.1.200/24
Operating System : CentOS 6.5 32 bit (Minimal Server) Hostname : slavedns.ostechnix.com IP Address : 192.168.1.201/24
[root@masterdns ~]# yum install bind* -y
The main configuration of the DNS will look like below. Edit and add the entries below which were marked as bold in this configuration files.
[root@masterdns ~]# vi /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; 192.168.1.200;}; ## Master DNS 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; 192.168.1.0/24; }; ## IP Range ## allow-transfer{ localhost; 192.168.1.201; }; ## Slave DNS 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"ostechnix.com" IN { type master; file "fwd.ostechnix.com"; allow-update { none; }; }; zone"1.168.192.in-addr.arpa" IN { type master; file "rev.ostechnix.com"; allow-update { none; }; }; include "/etc/named.rfc1912.zones"; include "/etc/named.root.key";
Now we should create forward and reverse zone files which we mentioned in the ‘/etc/named.conf’file.
[A] Create Forward Zone
Create ‘fwd.ostechnix.com’ file in the ‘/var/named’ directory and add the entries for forward zone as shown below.
[root@masterdns ~]# vi /var/named/fwd.ostechnix.com $TTL 86400 @ IN SOA masterdns.ostechnix.com. root.ostechnix.com. ( 2011071001 ;Serial 3600 ;Refresh 1800 ;Retry 604800 ;Expire 86400 ;Minimum TTL ) @IN NS masterdns.ostechnix.com. @IN NS slavedns.ostechnix.com.masterdns IN A 192.168.1.200 slavedns IN A 192.168.1.201
[B] Create Reverse Zone
Create ‘rev.ostechnix.com’ file in the ‘/var/named’ directory and add the entries for reverse zone as shown below.
[root@masterdns ~]# vi /var/named/rev.ostechnix.com $TTL 86400 @ IN SOA masterdns.ostechnix.com. root.ostechnix.com. ( 2011071001 ;Serial 3600 ;Refresh 1800 ;Retry 604800 ;Expire 86400 ;Minimum TTL ) @IN NS masterdns.ostechnix.com. @IN NS slavedns.ostechnix.com. masterdnsIN A 192.168.1.200 slavedns IN A 192.168.1.201 200 IN PTR masterdns.ostechnix.com. 201 IN PTR slavedns.ostechnix.com.
[root@masterdns ~]# service named start Generating /etc/rndc.key: [ OK ] Starting named: [ OK ] [root@masterdns ~]# chkconfig named on
Add the lines shown in bold letters in ‘/etc/sysconfig/iptables’ file. This will allow all clients to access the DNS server.
[root@masterdns ~]# vi /etc/sysconfig/iptables # Firewall configuration written by system-config-firewall # Manual customization of this file is not recommended. *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -p udp -m state --state NEW --dport 53 -j ACCEPT -A INPUT -p tcp -m state --state NEW --dport 53 -j ACCEPT -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT
[root@masterdns ~]# service iptables restart iptables: Flushing firewall rules: [ OK ] iptables: Setting chains to policy ACCEPT: filter [ OK ] iptables: Unloading modules: [ OK ] iptables: Applying firewall rules: [ OK ]
[root@masterdns ~]# named-checkconf /etc/named.conf [root@masterdns ~]# named-checkconf /etc/named.rfc1912.zones
[root@masterdns ~]# named-checkzone ostechnix.com /var/named/fwd.ostechnix.com zone ostechnix.com/IN: loaded serial 2011071001 OK [root@masterdns ~]# named-checkzone ostechnix.com /var/named/rev.ostechnix.com zone ostechnix.com/IN: loaded serial 2011071001 OK [root@masterdns ~]#
[root@masterdns ~]# dig masterdns.ostechnix.com ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> masterdns.ostechnix.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11496 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; QUESTION SECTION: ;masterdns.ostechnix.com.INA ;; ANSWER SECTION: masterdns.ostechnix.com. 86400INA192.168.1.200 ;; AUTHORITY SECTION: ostechnix.com.86400INNSmasterdns.ostechnix.com. ostechnix.com.86400INNSslavedns.ostechnix.com. ;; ADDITIONAL SECTION: slavedns.ostechnix.com.86400INA192.168.1.201 ;; Query time: 5 msec ;; SERVER: 192.168.1.200#53(192.168.1.200) ;; WHEN: Sun Mar 3 12:48:35 2013 ;; MSG SIZE rcvd: 110
[root@masterdns ~]# dig -x 192.168.1.200 ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> -x 192.168.1.200 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40891 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;200.1.168.192.in-addr.arpa.INPTR ;; ANSWER SECTION: 200.1.168.192.in-addr.arpa. 86400 INPTRmasterdns.ostechnix.com. ;; AUTHORITY SECTION: 1.168.192.in-addr.arpa.86400INNSmasterdns.ostechnix.com. 1.168.192.in-addr.arpa.86400INNSslavedns.ostechnix.com. ;; ADDITIONAL SECTION: masterdns.ostechnix.com. 86400INA192.168.1.200 slavedns.ostechnix.com.86400INA192.168.1.201 ;; Query time: 6 msec ;; SERVER: 192.168.1.200#53(192.168.1.200) ;; WHEN: Sun Mar 3 12:49:53 2013 ;; MSG SIZE rcvd: 150
[root@masterdns ~]# nslookup masterdns Server:192.168.1.200 Address:192.168.1.200#53 Name:masterdns.ostechnix.com Address: 192.168.1.200
Thats it. Now the Primary DNS server is ready
[root@slavedns ~]# yum install bind* -y
Open the main configuration file ‘/etc/named.conf’ and add the lines as shown in bold letters.
[root@slavedns ~]# vi /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; 192.168.1.201; }; ## Slve DNS 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; 192.168.1.0/24; }; ## IP Range ## 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"ostechnix.com" IN { type slave; file "slaves/ostechnix.fwd"; masters { 192.168.1.200; }; }; zone"1.168.192.in-addr.arpa" IN { type slave; file "slaves/ostechnix.rev"; masters { 192.168.1.200; }; }; include "/etc/named.rfc1912.zones"; include "/etc/named.root.key";
[root@slavedns ~]# service named start Generating /etc/rndc.key: [ OK ] Starting named: [ OK ] [root@slavedns ~]# chkconfig named on
Now the forward and reverse zones are automatically replicated from Master DNS server to Slave DNS server.
To verify, goto DNS database location(i.e ‘/var/named/slaves’) and use command ‘ls’.
[root@slavedns ~]# cd /var/named/slaves/ [root@slavedns slaves]# ls ostechnix.fwd ostechnix.rev
The forward and reverse zones are automatically replicated from Master DNS. Now check the zone files whether the correct zone files are replicated or not.
[A] Check Forward zone:
[root@slavedns slaves]# cat ostechnix.fwd $ORIGIN . $TTL 86400; 1 day ostechnix.comIN SOAmasterdns.ostechnix.com. root.ostechnix.com. ( 2011071001 ; serial 3600 ; refresh (1 hour) 1800 ; retry (30 minutes) 604800 ; expire (1 week) 86400 ; minimum (1 day) ) NSmasterdns.ostechnix.com. NSslavedns.ostechnix.com. $ORIGIN ostechnix.com. masterdnsA192.168.1.200 slavedns A192.168.1.201
[B] Check Reverse zone:
[root@slavedns slaves]# cat ostechnix.rev $ORIGIN . $TTL 86400; 1 day 1.168.192.in-addr.arpaIN SOAmasterdns.ostechnix.com. root.ostechnix.com. ( 2011071001 ; serial 3600 ; refresh (1 hour) 1800 ; retry (30 minutes) 604800 ; expire (1 week) 86400 ; minimum (1 day) ) NSmasterdns.ostechnix.com. NSslavedns.ostechnix.com. $ORIGIN 1.168.192.in-addr.arpa. 200PTRmasterdns.ostechnix.com. 201PTRslavedns.ostechnix.com. masterdnsA192.168.1.200 slavedns A192.168.1.201
[root@slavedns ~]# vi /etc/resolv.conf # Generated by NetworkManager search ostechnix.com nameserver 192.168.1.200 nameserver 192.168.1.201 nameserver 8.8.8.8
Method A:
[root@slavedns ~]# dig slavedns.ostechnix.com ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> slavedns.ostechnix.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39096 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; QUESTION SECTION: ;slavedns.ostechnix.com.INA ;; ANSWER SECTION: slavedns.ostechnix.com.86400INA192.168.1.201 ;; AUTHORITY SECTION: ostechnix.com.86400INNSmasterdns.ostechnix.com. ostechnix.com.86400INNSslavedns.ostechnix.com. ;; ADDITIONAL SECTION: masterdns.ostechnix.com. 86400INA192.168.1.200 ;; Query time: 7 msec ;; SERVER: 192.168.1.200#53(192.168.1.200) ;; WHEN: Sun Mar 3 13:00:17 2013 ;; MSG SIZE rcvd: 110
Method B:
[root@slavedns ~]# dig masterdns.ostechnix.com ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> masterdns.ostechnix.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12825 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; QUESTION SECTION: ;masterdns.ostechnix.com.INA ;; ANSWER SECTION: masterdns.ostechnix.com. 86400INA192.168.1.200 ;; AUTHORITY SECTION: ostechnix.com.86400INNSmasterdns.ostechnix.com. ostechnix.com.86400INNSslavedns.ostechnix.com. ;; ADDITIONAL SECTION: slavedns.ostechnix.com.86400INA192.168.1.201 ;; Query time: 13 msec ;; SERVER: 192.168.1.200#53(192.168.1.200) ;; WHEN: Sun Mar 3 13:01:02 2013 ;; MSG SIZE rcvd: 110
Method C:
[root@slavedns ~]# nslookup slavedns Server:192.168.1.200 Address:192.168.1.200#53 Name:slavedns.ostechnix.com Address: 192.168.1.201
Method D:
[root@slavedns ~]# nslookup masterdns Server:192.168.1.200 Address:192.168.1.200#53 Name:masterdns.ostechnix.com Address: 192.168.1.200
Method E:
[root@slavedns ~]# dig -x 192.168.1.201 ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> -x 192.168.1.201 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56991 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;201.1.168.192.in-addr.arpa.INPTR ;; ANSWER SECTION: 201.1.168.192.in-addr.arpa. 86400 INPTRslavedns.ostechnix.com. ;; AUTHORITY SECTION: 1.168.192.in-addr.arpa.86400INNSmasterdns.ostechnix.com. 1.168.192.in-addr.arpa.86400INNSslavedns.ostechnix.com. ;; ADDITIONAL SECTION: masterdns.ostechnix.com. 86400INA192.168.1.200 slavedns.ostechnix.com.86400INA192.168.1.201 ;; Query time: 6 msec ;; SERVER: 192.168.1.200#53(192.168.1.200) ;; WHEN: Sun Mar 3 13:03:39 2013 ;; MSG SIZE rcvd: 150
Method F:
[root@slavedns ~]# dig -x 192.168.1.200 ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> -x 192.168.1.200 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42968 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;200.1.168.192.in-addr.arpa.INPTR ;; ANSWER SECTION: 200.1.168.192.in-addr.arpa. 86400 INPTRmasterdns.ostechnix.com. ;; AUTHORITY SECTION: 1.168.192.in-addr.arpa.86400INNSslavedns.ostechnix.com. 1.168.192.in-addr.arpa.86400INNSmasterdns.ostechnix.com. ;; ADDITIONAL SECTION: masterdns.ostechnix.com. 86400INA192.168.1.200 slavedns.ostechnix.com.86400INA192.168.1.201 ;; Query time: 4 msec ;; SERVER: 192.168.1.200#53(192.168.1.200) ;; WHEN: Sun Mar 3 13:04:15 2013 ;; MSG SIZE rcvd: 150
That’s it. Both Primary and Secondary DNS Server is ready to use. Have a Good day!!!
Related Articles:
Rate this: