CREST Practitioner Security Analyst (CPSA) Practice

What does a Pointer Record (PTR) do?

1. Points from domain names to IP addresses

2. Maps IP addresses to host names

3. Stores email server configuration

4. Directs traffic to an alternate webpage

The correct answer is: Maps IP addresses to host names

A Pointer Record (PTR) serves the important function of mapping IP addresses to host names, which is essentially the reverse of what an Address Record (A Record) does, where domain names are linked to IP addresses. This functionality is crucial for various network applications, particularly in enabling reverse DNS lookups. When a device or server receives an IP address, it can utilize a PTR record to determine the associated domain name, aiding in verifying that the IP address and domain name correlate correctly. This mapping is vital for network management and can enhance security measures by providing an additional layer of verification when resources are accessed or when diagnosing network issues. PTR records play a significant role in email validation and anti-spam techniques, as they can help authenticate the server sending the email by checking if the sending IP address corresponds to the domain name it claims to have. While the other options describe functionalities that are either unrelated or pertain to different aspects of DNS operations, the function of pointing IP addresses to host names is specifically characteristic of PTR records, making it the correct and most relevant answer.