Certified Ethical Hacker (CEH) Practice Exam – Prep, Study Guide & Practice Questions

The function of a Pointer (PTR) record in the Domain Name System (DNS) is to map an IP address to a hostname. This reverse mapping is essential for various network operations, including logging, troubleshooting, and security applications.

When a device connects to the internet, it is often useful for the receiving system to know not just the IP address but also the corresponding domain name or hostname through which it can be identified. PTR records serve this purpose by allowing the DNS server to provide the hostname associated with a specific IP address when queried.

This is particularly used in reverse DNS lookups, which are important for checking the legitimacy of an IP address and improving email deliverability, among other applications. The other options focus on functions that do not relate to the primary purpose of a PTR record. For instance, mapping a domain name to an IP address is the function of an A (Address) record, while registering a new domain or verifying domain ownership are actions not associated with PTR records.