Which three servers are in scope for PCI DSS?

The correct answer focuses on the types of servers that directly handle, process, or transmit cardholder data, which is a key aspect of compliance with the Payment Card Industry Data Security Standard (PCI DSS).

Web servers, application servers, and database servers are integral parts of a traditional payment processing architecture. The web server handles incoming requests from clients and serves web pages that may contain cardholder data. The application server processes the business logic behind applications, potentially managing sensitive data transactions. The database server is where cardholder data, transaction details, and other relevant information are stored securely. As a result, all these servers are in scope for PCI DSS since they all play a crucial role in storing, processing, or transmitting sensitive payment information.

In contrast, the other options refer to server types that may not directly handle cardholder data or may be more peripheral to the payment processing infrastructure. For example, file servers and proxy servers may manage other data types or assist in network functions but do not necessarily process card transactions. Similarly, mail servers and backup servers might involve data security, but they do not directly interface with cardholder data in a way that requires PCI DSS compliance. Understanding the roles of different server types in the context of handling sensitive data is fundamental to determining