Exam 010-160 Topic 4 Question 40 Discussion

Explanation
The DNS record types that hold an IP address are the A and AAAA records. These records are used to map a domain name to an IP address of the host, which is necessary for establishing a connection between a client and a server. The A record holds a 32-bit IPv4 address, while the AAAA record holds a 128-bit IPv6 address.
For example, the A record for www.example.com could be:
www.example.com. IN A 192.0.2.1
This means that the domain name www.example.com resolves to the IPv4 address 192.0.2.1. Similarly, the AAAA record for www.example.com could be:
www.example.com. IN AAAA 2001:db8::1
This means that the domain name www.example.com resolves to the IPv6 address 2001:db8::1.
The other options are incorrect because:
* NS records are used to specify the authoritative name servers for a domain. They do not hold an IP address, but a domain name of the name server. For example, the NS record for example.com could be:
example.com. IN NS ns1.example.com.
This means that the name server ns1.example.com is authoritative for the domain example.com.
* MX records are used to specify the mail exchange servers for a domain. They do not hold an IP address, but a domain name of the mail server and a preference value. For example, the MX record for example.com could be:
example.com. IN MX 10 mail.example.com.
This means that the mail server mail.example.com has a preference value of 10 for receiving email for the domain example.com.
* CNAME records are used to create an alias for a domain name. They do not hold an IP address, but another domain name that the alias points to. For example, the CNAME record for www.example.com could be:
www.example.com. IN CNAME example.com.
This means that the domain name www.example.com is an alias for the domain name example.com.
References:
* DNS Record Types: Defined and Explained - Site24x7
* List of DNS record types - Wikipedia