[A] Primary(Master) DNS Server Details:
Operating System : CentOS 6.5 32 bit (Minimal Server)
Hostname : masterdns.ostechnix.com
IP Address : 192.168.1.200/24
[B] Secondary(Slave) DNS Server Details:
Operating System : CentOS 6.5 32 bit (Minimal Server)
Hostname : slavedns.ostechnix.com
IP Address : 192.168.1.201/24
Setup Primary(Master) DNS Server
[root@masterdns ~]# yum install bind* -y
1. Configure DNS Server
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";
2. Create Zone files
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.
3. Start the bind service
[root@masterdns ~]# service named start
Generating /etc/rndc.key: [ OK ]
Starting named: [ OK ]
[root@masterdns ~]# chkconfig named on
4. Allow DNS Server through iptables
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
5. Restart iptables to save the changes
[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 ]
6. Test syntax errors of DNS configuration and zone files
[A] Check DNS Config file
[root@masterdns ~]# named-checkconf /etc/named.conf
[root@masterdns ~]# named-checkconf /etc/named.rfc1912.zones
[B] Check zone files
[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 ~]#
7. Test DNS Server
Method A:
[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
Method B:
[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
Method C:
[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
Setup Secondary(Slave) DNS Server
[root@slavedns ~]# yum install bind* -y
1. Configure Slave DNS Server
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";
2. Start the DNS Service
[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
3. Add the DNS Server details to all systems
[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
4. Test DNS Server
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
資料來源：http://ostechnix.wordpress.com/2013/12/15/setup-dns-server-step-by-step-in-centos-6-3-rhel-6-3-scientific-linux-6-3-3/
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