• DNS - Domain Naming System. •

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Transcript of • 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

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

domain name into IP address.

DNS Configuration

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Forward zone lists the name

servers outside the network that

should be searched when the

networks name server fails.

DNS Configuration

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Service profile

• Packages - bind, bind-utils,

• caching-nameserver

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

• /var/named/named.local

• Daemons - named

• Port number - 53

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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

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Open this file for mentioning

the home directory for DNS.

DNS Configuration

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Here DNS home directory

is /var/named/chroot.

DNS Configuration

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View the home

directory files.

DNS Configuration

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Open the configuration

file named.conf.

DNS Configuration

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 Now you are seeing

the contents of 

named.conf file.

DNS Configuration

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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

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DNS Configuration

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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

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Save and exit the

file

DNS Configuration

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Copying the syntax file

named.local to example.for 

and example.rev.

DNS Configuration

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Open the forward

file.

DNS Configuration

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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

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Replace local host to fully

qualified name using asgiven below.

DNS Configuration

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 Now the localhost is replaced as

server1.example.com.

DNS Configuration

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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

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Open the

example.rev file.

DNS Configuration

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DNS Configuration

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Replace localhost to

server1.example.com using as below.

DNS Configuration

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 Now the localhost is replaced

  by server1.example.com.

DNS Configuration

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In a PTR record, you can specify

 just that last number segment of 

the address.

DNS Configuration

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Open the

resolve.conf file.

DNS Configuration

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Mention the nameserver 

ipaddress and domain name here.

DNS Configuration

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 Now named service

is restarted.

DNS Configuration

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Thus the DNS makes it possible to ping an

host by its domain name by resolving the

domain name into IP address.

DNS Configuration

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Thus the DNS makes it possible to ping an

host by its domain name by resolving the

domain name into IP address.

DNS Configuration

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dig command shows ip addressof the specified fully-qualified

domain name .

DNS Configuration

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 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.

Using nslookup you can identifies

FQDN for particular IP address.

DNS Configuration

fi i

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

domain name into IP address.

DNS Configuration

S C fi i

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In client side open the

/etc/resolv.conf file.

DNS Configuration

DNS C fi i

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Mention the nameserver 

ipaddress and domain name

here.

DNS Configuration

DNS C fi i

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Thus the DNS makes it possible to ping an

host by its domain name by resolving the

domain name into IP address.

DNS Configuration

DNS C fi i

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It shows the simple lookup of 

host,thus its show the

corresponding ip address to thespecified fully quailed domain

name.

Using nslookup you can identifies

MX record for particular domain.

Using nslookup you can identifiesnameserver for particular domain.

DNS Configuration

DNS C fi i

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Open the forward

file.

DNS Configuration

DNS C fi ti

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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

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Open the reverse

file.

DNS Configuration

DNS C fi ti

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Similarly we can add another 

 pointer record 105 for 

station105.example.com.

DNS Configuration

DNS C fi ti

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 Now named service

is restarted.

DNS Configuration

DNS C fi ti

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Using nslookup you can identifies

MX record for particular domain.Using nslookup you can identifies

address for particular FQDN.

Using nslookup you can identifies

PTR record for particular FQDN.

DNS Configuration

DNS C fi ti

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Open the configuration

file named.conf.

DNS Configuration