DNS

In localhost

1. WE NEED TO CHANGE ENTRIES OF /ETC/HOSTS FILE

127.0.0.1 localhost

127.0.0.1 localhost

10.2.0.30 cit

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IN LAN

1. sudo apt-get install dnsmasq

2. gedit /etc/dnsmasq.conf

3. Uncomment the following lines:

domain-needed
bogus-priv
no-resolv
no-poll
server=/example.com/192.168.0.5
server=8.8.8.8
server=208.67.220.220
local=/example.com/
address=/doubleclick.net/127.0.0.1
no-hosts
addn-hosts=/etc/dnsmasq.d/hosts.conf
expand-hosts
domain=example.com
dhcp-range=192.168.0.20,192.168.0.50,72h
dhcp-range=tftp,192.168.0.250,192.168.0.254  
hcp-host=mylaptop,192.168.0.199,36h
dhcp-option=option:router,192.168.0.1
dhcp-option=option:ntp-server,192.168.0.5
dhcp-option=19,0 # ip-forwarding off
dhcp-option=44,192.168.0.5 # set netbios-over-TCP/IP aka WINS
dhcp-option=45,192.168.0.5 # netbios datagram distribution server
dhcp-option=46,8           # netbios node type

4. gedit /etc/dnsmasq.d/hosts.conf

5. Add a list of local machines with static IP addresses in the same format as the hosts file

For exmaple:

192.168.0.8  mail mail.example.com
192.168.0.9  smtp smtp.example.com
192.168.0.120 mythtvbox mythtvbox.example.com

instead of the given IP's we need to add the addresses of those systems which are connected to the network.

6. sudo service dnsmasq start

7. sudo service dnsmasq stop

8. sudo service dnsmasq restart

9. You can now test using the adresses added in the hosts file.

Sorce: http://blogging.dragon.org.uk/howto-setup-dnsmasq-as-dns-dhcp/

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WITH A FOREIGN SERVER GIVEN(We have used Karizna):

1. sudo apt-get update

2. sudo apt-get install bind9

3. gedit /etc/bind/named.conf.options

4. Uncomment the following:

forwarders {
       8.8.8.8;
       8.8.4.4;
       };

5. sudo service bind9 restart

6. gedit /etc/resolv.conf

7. Edit nameserver ip to 127.0.0.1 or your serverIP.

nameserver 127.0.0.1

8. sudo cp /etc/bind/db.local /etc/bind/db.krizna.com

9. gedit /etc/bind/db.krizna.com

10. The edited version of the file:

; BIND data file for local loopback interface
;
$TTL    604800
@ IN SOA ns.krizna.com. root.ns.krizna.com. (
                              2         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
@       IN      NS      ns.krizna.com.
@       IN      A       192.168.6.5
@       IN      AAAA    ::1
ns      IN      A       192.168.6.5
www     IN	 A	192.168.6.10

11. sudo cp /etc/bind/db.127 /etc/bind/db.192

12. gedit /etc/bind/db.192

13. Edited version of the file:

; BIND reverse data file for local loopback interface
;
$TTL    604800
@ IN SOA ns.krizna.com. root.ns.krizna.com. (
                              1         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
@      IN      NS      ns.
5      IN      PTR     ns.krizna.com.
10     IN      PTR     www.krizna.com.

14. gedit /etc/bind/named.conf.local

15. Edited version of the file:

// Forward zone
zone "krizna.com" {
        type master;
        file "/etc/bind/db.krizna.com";
};
//reverse zone
zone "6.168.192.in-addr.arpa" {
        type master;
        file "/etc/bind/db.192";
}; 

instead of 6.168.192 add the first three octets of your network ip.

16. sudo service bind9 restart

17. Now test using nslookup command.

18. nslookup www.krizna.com

19. Output:

Server: 127.0.0.1
Address: 127.0.0.1#53
Name: www.krizna.com
Address: 192.168.6.10

20. nslookup 172.27.6.10

21. Output:

Server: 127.0.0.1
Address: 127.0.0.1#53
10.6.27.172.in-addr.arpa name = www.krizna.com.
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Source: http://www.krizna.com/ubuntu/configure-dns-server-ubuntu-14-04/