What is the purpose of a PTR record?

Performing a DNS lookup with dig results in this What might be wrong in the zone
definition?

What directive can be used in named.conf to restrict zone transfers to the 192.168.1.0/24
network?

To securely use dynamic DNS updates, the use of TSIG is recommended. Which TWO
statements about TSIG are true?

Which option is used to configure pppd to use up to two DNS server addresses provided by
the remote server?

A DNS server has the IP address 192.168.0.1. Which TWO of the following need to be done
on a client machine to use this DNS server?

The mailserver is currently called fred, while the primary MX record points to
mailhost.example.org. What must be done to direct example.org email towards fred?

Which of these ways can be used to only allow access to a DNS server from specified
networks/hosts?

There is a restricted area in an Apache site, which requires users to authenticate against
the file /srv/ www/security/site-passwd. Which command is used to CHANGE the password
of existing users, without losing data, when Basic authentication is being used.

Consider the following / srv/www/ default/html/ restricted/.htaccess AuthType Basic
AuthUserFile / srv/www/ security/ site-passwd AuthName Restricted Require valid-user
Order deny,allow Deny from all Allow from 10.1.2.0/24 Satisfy any Considering that
DocumentRoot is set to /srv/www/default/html, which TWO of the following sentences are
true?