CREST Practitioner Security Analyst (CPSA) Practice 2026 - Free CPSA Practice Questions and Study Guide

In the context of DNS, a reverse lookup refers to the process of determining the domain name associated with a given IP address. This is the opposite of a forward lookup, where a domain name is translated into an IP address. The correct answer, a Pointer Record (PTR), specifically serves this purpose.

A PTR record maps an IP address to its corresponding domain name, enabling reverse DNS lookups. When a reverse query is executed against the DNS to find the domain name associated with a specific IP address, the DNS server responds using the PTR record that contains that mapping.

The other types of records mentioned serve different purposes in DNS management. An A record is used for mapping a domain name to an IP address, which is forward resolution. A Mail Exchanger (MX) record specifies the mail server responsible for receiving email messages for a domain, and a Start of Authority (SOA) record contains administrative information about the domain, including the primary name server and certain timing parameters. These records do not facilitate reverse lookups and are therefore not applicable in this context.