• DNS - Domain Naming System. •

8/14/2019 • DNS - Domain Naming System. •

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DNS• DNS - Domain naming system.

• DNS service locates and translatesdomain names into correspondingassociated IP addresses.

• DNS configuration.

• It requires the following softwarepackages to be installed.• bind• Caching-name server• bind-utils



Thus the DNS makes it possible to ping anhost by its domain name by resolving the

domain name into IP address.

DNS Configuration



Forward zone lists the name

servers outside the network that

should be searched when the

networks name server fails.

DNS Configuration



Service profile

• Packages - bind, bind-utils,

• caching-nameserver

• Configuration files - /etc/named/named.conf

• /var/named/named.local

• Daemons - named

• Port number - 53



Install bind, this package

includes web page

manuals anddocumentation

Install bind-utils which

provides many utilities

like host, dig and nslookup

Install caching-name

server which provides a

working named.conf configuration file

DNS Configuration



Open this file for mentioning

the home directory for DNS.

DNS Configuration



Here DNS home directory

is /var/named/chroot.

DNS Configuration



View the home

directory files.

DNS Configuration



Open the configuration

file named.conf.

DNS Configuration



Now you are seeing

the contents of

named.conf file.

DNS Configuration



Forward zone mapping

between fully qualified

domain to particular ip

address.

This file contains

the ip address andthe locations of all

the dot servers.

DNS Configuration



DNS Configuration



Enter theforward file

name.

Copy and paste the forward

and reverse zones and edit

them as follows.Enter the

domain name

here.

Enter the IP

address in

reverse order.

Enter the

reverse file

name.

DNS Configuration



Save and exit the

file

DNS Configuration



Copying the syntax file

named.local to example.for

and example.rev.

DNS Configuration



Open the forward

file.

DNS Configuration



Enter the fully qualified

name of the name

server.It is interpreted as the

name of the originating

domain.

Enter the authorised name

server for this zone.

Enter the fully qualified

name of host.

Enter the last number segment

of the host address in thereverse zone file.

DNS Configuration



Replace local host to fully

qualified name using asgiven below.

DNS Configuration



Now the localhost is replaced as

server1.example.com.

DNS Configuration



Enter the ip address for

specified domain name.

Canonical name, is used to

define an alias for a hostname.

Set www as the cname for

server1.example.com.

DNS Configuration



Open the

example.rev file.

DNS Configuration



DNS Configuration



Replace localhost to

server1.example.com using as below.

DNS Configuration



Now the localhost is replaced

by server1.example.com.

DNS Configuration



In a PTR record, you can specify

just that last number segment of

the address.

DNS Configuration



Open the

resolve.conf file.

DNS Configuration



Mention the nameserver

ipaddress and domain name here.

DNS Configuration



Now named service

is restarted.

DNS Configuration



Thus the DNS makes it possible to ping an

host by its domain name by resolving the


DNS Configuration






DNS Configuration



dig command shows ip addressof the specified fully-qualified

domain name .

DNS Configuration



Nslookup is a dns diagnostic tool

used to query a dns server.

Using nslookup you can identifies

nameserver for particular doamin.Using nslookup you can identifies

address for particular FQDN.


FQDN for particular IP address.

DNS Configuration

fi i



Thus the DNS makes it possible to ping anhost by its domain name by resolving the


DNS Configuration

S C fi i



In client side open the

/etc/resolv.conf file.

DNS Configuration

DNS C fi i



Mention the nameserver

ipaddress and domain name

here.

DNS Configuration

DNS C fi i






DNS Configuration

DNS C fi i



It shows the simple lookup of

host,thus its show the

corresponding ip address to thespecified fully quailed domain

name.


MX record for particular domain.

Using nslookup you can identifiesnameserver for particular domain.

DNS Configuration

DNS C fi i



Open the forward

file.

DNS Configuration

DNS C fi ti



In this file we can add additional

entry MX(mail exchange record )

and its corresponding ip address

192.168.0.100.In this file we can add additional

entry station105 machine and its

corresponding ip address

192.168.0.100

DNS Configuration

DNS C fi ti



Open the reverse

file.

DNS Configuration

DNS C fi ti



Similarly we can add another

pointer record 105 for

station105.example.com.

DNS Configuration

DNS C fi ti



Now named service

is restarted.

DNS Configuration

DNS C fi ti




MX record for particular domain.Using nslookup you can identifies

address for particular FQDN.


PTR record for particular FQDN.

DNS Configuration

DNS C fi ti



Open the configuration

file named.conf.

DNS Configuration

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• DNS - Domain Naming System. •