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Do the following steps as:

1.visudo

# User alias Specification

User_alias LIMITEDTRUST=peter

# Cmnd alias Specification

Cmnd_alias MINIMUM=/usr/sbin/useradd, /usr/bin/passwd, /usr/sbin/groupadd, /usr/sbin/userdel, /usr/sbin/groupdel, /usr/sbin/usermod

#User Privilege Specification

LIMITEDTRUST ALL=MINIMUM

2.Login as peter user and run sudo useradd username

Using Sudo we can give root level privilege on commands. Visudo is the sudo editor. In user alias Specification we create the user alias and in Cmnd alias Specification, we create the command alias. In User Privilege Specification section, list the users, groups allowed to use the sudo.

Do the following steps as:

1.rename the file named.caching-nameserver.conf into named.conf file located into /var/named/chroot/etc

#mv /var/named/chroot/etc/named.caching-nameserver.conf /var/named/chroot/etc/named.conf

2. Check the permission and ownership as well as SELinux Context should be like as:

-rw-r----- root named system_u:object_r:named_conf_t /var/named/chroot/etc/named.conf

If selinux context is mismatch use the restorecon –R /var command

3. vi /var/named/chroot/etc/named.conf

zone “example.com” IN {

type master;

file “example.com.zone”;

};

/var/named/chroot/etc/named.conf file is used to register the zone as well as specify theglobal option for DNS server. There are two types of zone, i. Master, which contains the original data. ii. Slave, backup of master. Here is the example of master zone configuration.

4.vi /var/named/chroot/var/named/example.com.zone

$TTL 345345

@ IN SOA @ webmaster.example.com.(

101;Serial Number

1H;Refresh Time

1M;Retry Time

1W;Expire Time

1D;Minimum Time to Live

)

@ IN NS 192.100.0.X

www IN A 192.100.0.20

5. Check the permission as well as SELinux Context should like this:

-rw-r--r-- root named root:object_r:named_zone_t /var/named/chroot/var/named/example.com.zone

If selinux context is mismatch use the restorecon –R /var command

6.service named start

7.rndc reload

8.chkconfig named on

Zone file should create on /var/named/chroot/var/named. Default Directory Path is specified on /var/named/chroot/etc/named.conf file.

$TTLTime To Live, How much seconds cache server stores the information about DNS. And Five Parameters specified Serial Number used by slave to synchronize with master server. Refresh and Retry Time used by slave server. NS is the Name (DNS) server where lookup the domain. A (Associated IP) for particular host.