{"id":57,"date":"2014-09-19T17:33:00","date_gmt":"2014-09-19T17:33:00","guid":{"rendered":"http:\/\/onlinelab.info\/2014\/09\/19\/setting-up-dns-server-on-centos-7\/"},"modified":"2014-09-19T17:33:00","modified_gmt":"2014-09-19T17:33:00","slug":"setting-up-dns-server-on-centos-7","status":"publish","type":"post","link":"https:\/\/www.asianux.org.vn\/index.php\/2014\/09\/19\/setting-up-dns-server-on-centos-7\/","title":{"rendered":"Setting Up DNS Server On CentOS 7"},"content":{"rendered":"

<\/p>\n

For the purpose of this tutorial, I will be using three nodes. One will be acting as Master DNS server, the second system will be acting as Secondary DNS, and the third will be our DNS client. Here are my three systems details.<\/span><\/div>\n
Primary (Master) DNS Server Details:<\/span><\/b><\/div>\n
Operating System     : CentOS 7 minimal server<\/span><\/div>\n
Hostname             : masterdns.sysadmin.com.vn<\/span><\/div>\n
IP Address           : 192.168.1.101\/24<\/span><\/div>\n
Secondary (Slave) DNS Server Details:<\/span><\/b><\/div>\n
Operating System     : CentOS 7 minimal server<\/span><\/div>\n
Hostname             : secondarydns.sysadmin.com.vn<\/span><\/div>\n
IP Address           : 192.168.1.102\/24<\/span><\/div>\n
Client Details:<\/span><\/b><\/div>\n
Operating System     : CentOS 6.5 Desktop  <\/span><\/div>\n
Hostname             : client.sysadmin.com.vn<\/span><\/div>\n
IP Address           : 192.168.1.103\/24<\/span><\/div>\n
Setup Primary (Master) DNS Server<\/span><\/b><\/div>\n
Install bind9 packages on your server.<\/span><\/div>\n
yum install bind bind-utils -y<\/span><\/div>\n
1. Configure DNS Server<\/span><\/b><\/div>\n
Edit \u2018\/etc\/named.conf\u2019<\/b> file.<\/span><\/div>\n
vi \/etc\/named.conf<\/span><\/div>\n
Add the lines as shown in bold:<\/span><\/div>\n
\/\/<\/span><\/div>\n
\/\/ named.conf<\/span><\/div>\n
\/\/<\/span><\/div>\n
\/\/ Provided by Red Hat bind package to configure the ISC BIND named(8) DNS<\/span><\/div>\n
\/\/ server as a caching only nameserver (as a localhost DNS resolver only).<\/span><\/div>\n
\/\/<\/span><\/div>\n
\/\/ See \/usr\/share\/doc\/bind*\/sample\/ for example named configuration files.<\/span><\/div>\n
\/\/<\/span><\/div>\n
<\/div>\n
options {<\/span><\/div>\n
    listen-on port 53 { 127.0.0.1; 192.168.1.101;<\/b>}; ### Master DNS IP ###<\/b><\/span><\/div>\n
#    listen-on-v6 port 53 { ::1; };<\/span><\/div>\n
    directory     “\/var\/named”;<\/span><\/div>\n
    dump-file     “\/var\/named\/data\/cache_dump.db”;<\/span><\/div>\n
    statistics-file “\/var\/named\/data\/named_stats.txt”;<\/span><\/div>\n
    memstatistics-file “\/var\/named\/data\/named_mem_stats.txt”;<\/span><\/div>\n
    allow-query     { localhost; 192.168.1.0\/24;<\/b>}; ### IP Range ###<\/b><\/span><\/div>\n
    allow-transfer{ localhost; 192.168.1.102;<\/b> };   ### Slave DNS IP ###<\/b><\/span><\/div>\n
<\/div>\n
    \/* <\/span><\/div>\n
     – If you are building an AUTHORITATIVE DNS server, do NOT enable recursion.<\/span><\/div>\n
     – If you are building a RECURSIVE (caching) DNS server, you need to enable <\/span><\/div>\n
       recursion. <\/span><\/div>\n
     – If your recursive DNS server has a public IP address, you MUST enable access <\/span><\/div>\n
       control to limit queries to your legitimate users. Failing to do so will<\/span><\/div>\n
       cause your server to become part of large scale DNS amplification <\/span><\/div>\n
       attacks. Implementing BCP38 within your network would greatly<\/span><\/div>\n
       reduce such attack surface <\/span><\/div>\n
    *\/<\/span><\/div>\n
    recursion yes;<\/span><\/div>\n
<\/div>\n
    dnssec-enable yes;<\/span><\/div>\n
    dnssec-validation yes;<\/span><\/div>\n
    dnssec-lookaside auto;<\/span><\/div>\n
<\/div>\n
    \/* Path to ISC DLV key *\/<\/span><\/div>\n
    bindkeys-file “\/etc\/named.iscdlv.key”;<\/span><\/div>\n
<\/div>\n
    managed-keys-directory “\/var\/named\/dynamic”;<\/span><\/div>\n
<\/div>\n
    pid-file “\/run\/named\/named.pid”;<\/span><\/div>\n
    session-keyfile “\/run\/named\/session.key”;<\/span><\/div>\n
};<\/span><\/div>\n
<\/div>\n
logging {<\/span><\/div>\n
        channel default_debug {<\/span><\/div>\n
                file “data\/named.run”;<\/span><\/div>\n
                severity dynamic;<\/span><\/div>\n
        };<\/span><\/div>\n
};<\/span><\/div>\n
<\/div>\n
zone “.” IN {<\/span><\/div>\n
    type hint;<\/span><\/div>\n
    file “named.ca”;<\/span><\/div>\n
};<\/span><\/div>\n
<\/div>\n
zone “sysadmin.com.vn” IN {<\/span><\/b><\/div>\n
type master;<\/span><\/b><\/div>\n
file “forward.unixmen”;<\/span><\/b><\/div>\n
allow-update { none; };<\/span><\/b><\/div>\n
};<\/span><\/b><\/div>\n
zone “1.168.192.in-addr.arpa” IN {<\/span><\/b><\/div>\n
type master;<\/span><\/b><\/div>\n
file “reverse.unixmen”;<\/span><\/b><\/div>\n
allow-update { none; };<\/span><\/b><\/div>\n
};<\/span><\/b><\/span><\/div>\n
<\/div>\n
include “\/etc\/named.rfc1912.zones”;<\/span><\/div>\n
include “\/etc\/named.root.key”;<\/span><\/div>\n
2. Create Zone files<\/span><\/b><\/div>\n
Create forward and reverse zone files which we mentioned in the \u2018\/etc\/named.conf\u2019<\/b> file.<\/span><\/div>\n
2.1 Create Forward Zone<\/span><\/b><\/div>\n
Create forward.unixmen<\/b> file in the \u2018\/var\/named\u2019<\/b> directory.<\/span><\/div>\n
vi \/var\/named\/forward.unixmen<\/span><\/div>\n
Add the following lines:<\/span><\/div>\n
$TTL 86400<\/span><\/div>\n
@   IN  SOA     masterdns.sysadmin.com.vn. root.sysadmin.com.vn. (<\/span><\/div>\n
        2011071001  ;Serial<\/span><\/div>\n
        3600        ;Refresh<\/span><\/div>\n
        1800        ;Retry<\/span><\/div>\n
        604800      ;Expire<\/span><\/div>\n
        86400       ;Minimum TTL<\/span><\/div>\n
)<\/span><\/div>\n
@       IN  NS          masterdns.sysadmin.com.vn.<\/span><\/div>\n
@       IN  NS          secondarydns.sysadmin.com.vn.<\/span><\/div>\n
@       IN  A           192.168.1.101<\/span><\/div>\n
@       IN  A           192.168.1.102<\/span><\/div>\n
@       IN  A           192.168.1.103<\/span><\/div>\n
masterdns       IN  A   192.168.1.101<\/span><\/div>\n
secondarydns    IN  A   192.168.1.102<\/span><\/div>\n
client          IN  A   192.168.1.103<\/span><\/div>\n
2.2 Create Reverse Zone<\/span><\/b><\/div>\n
Create reverse.unixmen<\/b> file in the \u2018\/var\/named\u2019<\/b> directory.<\/span><\/div>\n
vi \/var\/named\/reverse.unixmen<\/span><\/div>\n
Add the following lines:<\/span><\/div>\n
$TTL 86400<\/span><\/div>\n
@   IN  SOA     masterdns.sysadmin.com.vn. root.sysadmin.com.vn. (<\/span><\/div>\n
        2011071001  ;Serial<\/span><\/div>\n
        3600        ;Refresh<\/span><\/div>\n
        1800        ;Retry<\/span><\/div>\n
        604800      ;Expire<\/span><\/div>\n
        86400       ;Minimum TTL<\/span><\/div>\n
)<\/span><\/div>\n
@       IN  NS          masterdns.sysadmin.com.vn.<\/span><\/div>\n
@       IN  NS          secondarydns.sysadmin.com.vn.<\/span><\/div>\n
@       IN  PTR         sysadmin.com.vn.<\/span><\/div>\n
masterdns       IN  A   192.168.1.101<\/span><\/div>\n
secondarydns    IN  A   192.168.1.102<\/span><\/div>\n
client          IN  A   192.168.1.103<\/span><\/div>\n
101     IN  PTR         masterdns.sysadmin.com.vn.<\/span><\/div>\n
102     IN  PTR         secondarydns.sysadmin.com.vn.<\/span><\/div>\n
103     IN  PTR         client.sysadmin.com.vn.<\/span><\/div>\n
3. Start the DNS service<\/span><\/b><\/div>\n
Enable and start DNS service:<\/span><\/div>\n
systemctl enable named<\/span><\/div>\n
systemctl start named<\/span><\/div>\n
4. Firewall Configuration<\/span><\/b><\/div>\n
We must allow the DNS service default port 53 through firewall.<\/span><\/div>\n
firewall-cmd –permanent –add-port=53\/tcp<\/span><\/div>\n
5. Restart Firewall<\/span><\/b><\/div>\n
firewall-cmd –reload<\/span><\/div>\n
6. Configuring Permissions, Ownership, and SELinux<\/span><\/b><\/div>\n
Run the following commands one by one:<\/span><\/div>\n
chgrp named -R \/var\/named<\/span><\/div>\n
chown -v root:named \/etc\/named.conf<\/span><\/div>\n
restorecon -rv \/var\/named<\/span><\/span><\/div>\n
restorecon \/etc\/named.conf<\/span><\/div>\n
7. Test DNS configuration and zone files for any syntax errors<\/span><\/b><\/div>\n
Check DNS default configuration file:<\/span><\/div>\n
named-checkconf \/etc\/named.conf<\/span><\/div>\n
If it returns nothing, your configuration file is valid.<\/span><\/div>\n
Check Forward zone:<\/span><\/div>\n
named-checkzone sysadmin.com.vn \/var\/named\/forward.unixmen<\/span><\/div>\n
Sample output:<\/span><\/div>\n
zone sysadmin.com.vn\/IN: loaded serial 2011071001<\/span><\/div>\n
OK<\/span><\/div>\n
Check reverse zone:<\/span><\/div>\n
named-checkzone sysadmin.com.vn \/var\/named\/reverse.unixmen <\/span><\/div>\n
Sam
\nple Output:<\/span><\/div>\n
zone sysadmin.com.vn\/IN: loaded serial 2011071001<\/span><\/div>\n
OK<\/span><\/div>\n
Add the DNS Server details in your network interface config file.<\/span><\/div>\n
vi \/etc\/sysconfig\/network-scripts\/ifcfg-enp0s3<\/span><\/div>\n
TYPE=”Ethernet”<\/span><\/div>\n
BOOTPROTO=”none”<\/span><\/div>\n
DEFROUTE=”yes”<\/span><\/div>\n
IPV4_FAILURE_FATAL=”no”<\/span><\/div>\n
IPV6INIT=”yes”<\/span><\/div>\n
IPV6_AUTOCONF=”yes”<\/span><\/div>\n
IPV6_DEFROUTE=”yes”<\/span><\/div>\n
IPV6_FAILURE_FATAL=”no”<\/span><\/div>\n
NAME=”enp0s3″<\/span><\/div>\n
UUID=”5d0428b3-6af2-4f6b-9fe3-4250cd839efa”<\/span><\/div>\n
ONBOOT=”yes”<\/span><\/div>\n
HWADDR=”08:00:27:19:68:73″<\/span><\/div>\n
IPADDR0=”192.168.1.101″<\/span><\/div>\n
PREFIX0=”24″<\/span><\/div>\n
GATEWAY0=”192.168.1.1″<\/span><\/div>\n
DNS=”192.168.1.101″<\/span><\/b><\/span><\/div>\n
IPV6_PEERDNS=”yes”<\/span><\/div>\n
IPV6_PEERROUTES=”yes”<\/span><\/div>\n
Edit file \/etc\/resolv.conf<\/b>,<\/span><\/div>\n
vi \/etc\/resolv.conf<\/span><\/div>\n
Add the name server ip address:<\/span><\/div>\n
nameserver      192.168.1.101<\/span><\/div>\n
Save and close the file.<\/span><\/div>\n
Restart network service:<\/span><\/div>\n
systemctl restart network<\/span><\/div>\n
8. Test DNS Server<\/span><\/b><\/div>\n
dig masterdns.sysadmin.com.vn<\/span><\/div>\n
Sample Output:<\/span><\/div>\n
; <<>> DiG 9.9.4-RedHat-9.9.4-14.el7 <<>> masterdns.sysadmin.com.vn<\/span><\/div>\n
;; global options: +cmd<\/span><\/div>\n
;; Got answer:<\/span><\/div>\n
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 25179<\/span><\/div>\n
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2<\/span><\/div>\n
<\/div>\n
;; OPT PSEUDOSECTION:<\/span><\/div>\n
; EDNS: version: 0, flags:; udp: 4096<\/span><\/div>\n
;; QUESTION SECTION:<\/span><\/div>\n
;masterdns.sysadmin.com.vn.    IN    A<\/span><\/div>\n
<\/div>\n
;; ANSWER SECTION:<\/span><\/div>\n
masterdns.sysadmin.com.vn. 86400    IN    A    192.168.1.101<\/span><\/div>\n
<\/div>\n
;; AUTHORITY SECTION:<\/span><\/div>\n
sysadmin.com.vn.        86400    IN    NS    secondarydns.sysadmin.com.vn.<\/span><\/div>\n
sysadmin.com.vn.        86400    IN    NS    masterdns.sysadmin.com.vn.<\/span><\/div>\n
<\/div>\n
;; ADDITIONAL SECTION:<\/span><\/div>\n
secondarydns.sysadmin.com.vn. 86400 IN    A    192.168.1.102<\/span><\/div>\n
<\/div>\n
;; Query time: 0 msec<\/span><\/div>\n
;; SERVER: 192.168.1.101#53(192.168.1.101)<\/span><\/div>\n
;; WHEN: Wed Aug 20 16:20:46 IST 2014<\/span><\/div>\n
;; MSG SIZE  rcvd: 125<\/span><\/div>\n
nslookup sysadmin.com.vn<\/span><\/div>\n
Sample Output:<\/span><\/div>\n
Server:        192.168.1.101<\/span><\/div>\n
Address:    192.168.1.101#53<\/span><\/div>\n
<\/div>\n
Name:    sysadmin.com.vn<\/span><\/div>\n
Address: 192.168.1.103<\/span><\/div>\n
Name:    sysadmin.com.vn<\/span><\/div>\n
Address: 192.168.1.101<\/span><\/div>\n
Name:    sysadmin.com.vn<\/span><\/div>\n
Address: 192.168.1.102<\/span><\/div>\n
Now the Primary DNS server is ready to use.<\/span><\/div>\n
It is time to configure our Secondary DNS server.<\/span><\/div>\n
Setup Secondary(Slave) DNS Server<\/span><\/b><\/div>\n
Install bind packages using the following command:<\/span><\/div>\n
yum install bind bind-utils -y<\/span><\/div>\n
1. Configure Slave DNS Server<\/span><\/b><\/div>\n
Edit file \u2018\/etc\/named.conf\u2019<\/b>:<\/span><\/div>\n
vi \/etc\/named.conf<\/span><\/div>\n
Make the changes as shown in bold.<\/span><\/div>\n
\/\/<\/span><\/div>\n
\/\/ named.conf<\/span><\/div>\n
\/\/<\/span><\/div>\n
\/\/ Provided by Red Hat bind package to configure the ISC BIND named(8) DNS<\/span><\/div>\n
\/\/ server as a caching only nameserver (as a localhost DNS resolver only).<\/span><\/div>\n
\/\/<\/span><\/div>\n
\/\/ See \/usr\/share\/doc\/bind*\/sample\/ for example named configuration files.<\/span><\/div>\n
\/\/<\/span><\/div>\n
options {<\/span><\/div>\n
listen-on port 53 { 127.0.0.1; 192.168.1.102;<\/b> };<\/span><\/div>\n
listen-on-v6 port 53 { ::1; };<\/span><\/div>\n
directory “\/var\/named”;<\/span><\/div>\n
dump-file “\/var\/named\/data\/cache_dump.db”;<\/span><\/div>\n
        statistics-file “\/var\/named\/data\/named_stats.txt”;<\/span><\/div>\n
        memstatistics-file “\/var\/named\/data\/named_mem_stats.txt”;<\/span><\/div>\n
allow-query     { localhost; 192.168.1.0\/24;<\/b> };<\/span><\/div>\n
.<\/span><\/div>\n
.<\/span><\/div>\n
.<\/span><\/div>\n
.<\/span><\/div>\n
zone “.” IN {<\/span><\/div>\n
type hint;<\/span><\/div>\n
file “named.ca”;<\/span><\/div>\n
};<\/span><\/div>\n
zone “sysadmin.com.vn” IN {<\/span><\/b><\/div>\n
type slave;<\/span><\/b><\/div>\n
file “slaves\/unixmen.fwd”;<\/span><\/b><\/div>\n
masters { 192.168.1.101; };<\/span><\/b><\/div>\n
};<\/span><\/b><\/div>\n
zone “1.168.192.in-addr.arpa” IN {<\/span><\/b><\/div>\n
type slave;<\/span><\/b><\/div>\n
file “slaves\/unixmen.rev”;<\/span><\/b><\/div>\n
masters { 192.168.1.101; };<\/span><\/b><\/div>\n
};<\/span><\/b><\/span><\/div>\n
include “\/etc\/named.rfc1912.zones”;<\/span><\/div>\n
include “\/etc\/named.root.key”;<\/span><\/div>\n
2. Start the DNS Service<\/span><\/b><\/div>\n
systemctl enable named<\/span><\/div>\n
systemctl start named<\/span><\/div>\n
Now the forward and reverse zones are automatically replicated from Master DNS server to \u2018\/var\/named\/slaves\/\u2019 in Secondary DNS server.<\/span><\/div>\n
ls \/var\/named\/slaves\/<\/span><\/div>\n
Sample Output:<\/span><\/div>\n
unixmen.fwd  unixmen.rev<\/span><\/div>\n
3. Add the DNS Server details<\/span><\/b><\/div>\n
Add the DNS Server details in your network interface config file.<\/span><\/div>\n
vi \/etc\/sysconfig\/network-scripts\/ifcfg-enp0s3<\/span><\/div>\n
TYPE=”Ethernet”<\/span><\/div>\n
BOOTPROTO=”none”<\/span><\/div>\n
DEFROUTE=”yes”<\/span><\/div>\n
IPV4_FAILURE_FATAL=”no”<\/span><\/div>\n
IPV6INIT=”yes”<\/span><\/div>\n
IPV6_AUTOCONF=”yes”<\/span><\/div>\n
IPV6_DEFROUTE=”yes”<\/span><\/div>\n
IPV6_FAILURE_FATAL=”no”<\/span><\/div>\n
NAME=”enp0s3″<\/span><\/div>\n
UUID=”5d0428b3-6af2-4f6b-9fe3-4250cd839efa”<\/span><\/div>\n
ONBOOT=”yes”<\/span><\/div>\n
HWADDR=”08:00:27:19:68:73″<\/span><\/div>\n
IPADDR0=”192.168.1.102″<\/span><\/div>\n
PREFIX0=”24″<\/span><\/div>\n
GATEWAY0=”192.168.1.1″<\/span><\/div>\n
DNS1=”192.168.1.101″<\/span><\/b><\/div>\n
DNS2=”192.168.1.102″<\/span><\/b><\/div>\n
IPV6_PEERDNS=”yes”<\/span><\/div>\n
IPV6_PEERROUTES=”yes”<\/span><\/div>\n
Edit file \/etc\/resolv.conf<\/b>,<\/span><\/div>\n
vi \/etc\/resolv.conf<\/span><\/div>\n
Add the name server ip address:<\/span><\/div>\n
nameserver      192.168.1.101<\/span><\/div>\n
nameserver      192.168.1.102<\/span><\/div>\n
Save and close the file.<\/span><\/div>\n
Restart network service:<\/span><\/div>\n
systemctl restart network<\/span><\/div>\n
4. Firewall Configuration<\/span><\/b><\/div>\n
We must allow the DNS service default port 53 through firewall.<\/span><\/div>\n
firewall-cmd –permanent –add-port=53\/tcp<\/span><\/div>\n
5. Restart Firewall<\/span><\/b><\/div>\n
firewall-cmd –reload<\/span><\/div>\n
6. Configuring Permissions, Ownership, and SELinux<\/span><\/b><\/div>\n
chgrp named -R \/var\/named<\/span><\/div>\n
chown -v root:named \/etc\/named.conf<\/span><\/div>\n
restorecon -rv \/var\/named<\/span><\/span><\/div>\n
restorecon \/etc\/named.conf<\/span><\/div>\n
7. Test DNS Server<\/span><\/b><\/div>\n
dig masterdns.sysadmin.com.vn<\/span><\/div>\n
Sample Output:<\/span><\/div>\n
; <<>> DiG 9.9.4-RedHat-9.9.4-14.el7 <<>> masterdns.sysadmin.com.vn<\/span><\/div>\n

<\ndiv style=\"background: #FCFCFC; line-height: 15.0pt; margin-bottom: 7.5pt; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; word-break: break-all;\">;; global options: +cmd<\/span><\/div>\n

;; Got answer:<\/span><\/div>\n
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 18204<\/span><\/div>\n
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2<\/span><\/div>\n
<\/div>\n
;; OPT PSEUDOSECTION:<\/span><\/div>\n
; EDNS: version: 0, flags:; udp: 4096<\/span><\/div>\n
;; QUESTION SECTION:<\/span><\/div>\n
;masterdns.sysadmin.com.vn.    IN    A<\/span><\/div>\n
<\/div>\n
;; ANSWER SECTION:<\/span><\/div>\n
masterdns.sysadmin.com.vn. 86400    IN    A    192.168.1.101<\/span><\/div>\n
<\/div>\n
;; AUTHORITY SECTION:<\/span><\/div>\n
sysadmin.com.vn.        86400    IN    NS    masterdns.sysadmin.com.vn.<\/span><\/div>\n
sysadmin.com.vn.        86400    IN    NS    secondarydns.sysadmin.com.vn.<\/span><\/div>\n
<\/div>\n
;; ADDITIONAL SECTION:<\/span><\/div>\n
secondarydns.sysadmin.com.vn. 86400 IN    A    192.168.1.102<\/span><\/div>\n
<\/div>\n
;; Query time: 0 msec<\/span><\/div>\n
;; SERVER: 192.168.1.102#53(192.168.1.102)<\/span><\/div>\n
;; WHEN: Wed Aug 20 17:04:30 IST 2014<\/span><\/div>\n
;; MSG SIZE  rcvd: 125<\/span><\/div>\n
dig secondarydns.sysadmin.com.vn<\/span><\/div>\n
Sample Output:<\/span><\/div>\n
; <<>> DiG 9.9.4-RedHat-9.9.4-14.el7 <<>> secondarydns.sysadmin.com.vn<\/span><\/div>\n
;; global options: +cmd<\/span><\/div>\n
;; Got answer:<\/span><\/div>\n
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60819<\/span><\/div>\n
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2<\/span><\/div>\n
<\/div>\n
;; OPT PSEUDOSECTION:<\/span><\/div>\n
; EDNS: version: 0, flags:; udp: 4096<\/span><\/div>\n
;; QUESTION SECTION:<\/span><\/div>\n
;secondarydns.sysadmin.com.vn.    IN    A<\/span><\/div>\n
<\/div>\n
;; ANSWER SECTION:<\/span><\/div>\n
secondarydns.sysadmin.com.vn. 86400 IN    A    192.168.1.102<\/span><\/div>\n
<\/div>\n
;; AUTHORITY SECTION:<\/span><\/div>\n
sysadmin.com.vn.   &
\nnbsp;    86400    IN    NS    masterdns.sysadmin.com.vn.<\/span><\/div>\n
sysadmin.com.vn.        86400    IN    NS    secondarydns.sysadmin.com.vn.<\/span><\/div>\n
<\/div>\n
;; ADDITIONAL SECTION:<\/span><\/div>\n
masterdns.sysadmin.com.vn. 86400    IN    A    192.168.1.101<\/span><\/div>\n
<\/div>\n
;; Query time: 0 msec<\/span><\/div>\n
;; SERVER: 192.168.1.102#53(192.168.1.102)<\/span><\/div>\n
;; WHEN: Wed Aug 20 17:05:50 IST 2014<\/span><\/div>\n
;; MSG SIZE  rcvd: 125<\/span><\/div>\n
nslookup sysadmin.com.vn<\/span><\/div>\n
Sample Output:<\/span><\/div>\n
Server:        192.168.1.102<\/span><\/div>\n
Address:    192.168.1.102#53<\/span><\/div>\n
<\/div>\n
Name:    sysadmin.com.vn<\/span><\/div>\n
Address: 192.168.1.101<\/span><\/div>\n
Name:    sysadmin.com.vn<\/span><\/div>\n
Address: 192.168.1.103<\/span><\/div>\n
Name:    sysadmin.com.vn<\/span><\/div>\n
Address: 192.168.1.102<\/span><\/div>\n
Client Side Configuration<\/span><\/b><\/div>\n
Add the DNS server details in \u2018\/etc\/resolv.conf\u2019<\/b> file in all client systems<\/span><\/div>\n
vi \/etc\/resolv.conf<\/span><\/div>\n
# Generated by NetworkManager<\/span><\/div>\n
search sysadmin.com.vn<\/span><\/div>\n
nameserver 192.168.1.101<\/span><\/div>\n
nameserver 192.168.1.102<\/span><\/div>\n
Restart network service or reboot the system.<\/span><\/div>\n
Test DNS Server<\/span><\/b><\/div>\n
Now, you can test the DNS server using any one of the following commands:<\/span><\/div>\n
dig masterdns.sysadmin.com.vn<\/span><\/div>\n
dig secondarydns.sysadmin.com.vn<\/span><\/div>\n
dig client.sysadmin.com.vn<\/span><\/div>\n
nslookup sysadmin.com.vn<\/span><\/div>\n
That\u2019s all about now. The primary and secondary DNS servers are ready to use.<\/span><\/div>\n
Cheers!h<\/span><\/div>\n
<\/div>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

For the purpose of this tutorial, I will be using three nodes. One will be acting as Master DNS server, the second system will be acting as Secondary DNS, and the third will be our…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-57","post","type-post","status-publish","format-standard","hentry","category-linux"],"_links":{"self":[{"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/posts\/57","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/comments?post=57"}],"version-history":[{"count":0,"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/posts\/57\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/media?parent=57"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/categories?post=57"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.asianux.org.vn\/index.php\/wp-json\/wp\/v2\/tags?post=57"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}