Which log file contains syslog messages that pertain to security and authentication?

The log file that contains syslog messages pertaining to security and authentication is clearly identified as /var/log/secure. This log plays a crucial role in monitoring security-related events on the system. It records authentication attempts, including successful logins, failed login attempts, and other security-related events such as sudo commands and user account changes.

This centralization of security and authentication messages in /var/log/secure helps administrators monitor and respond to potential security issues more effectively. By regularly reviewing this log, system administrators can detect unauthorized access attempts or suspicious activity, enabling them to take appropriate actions to enhance system security.

The other options either do not specifically focus on security and authentication or pertain to different types of logs. For example, /var/log/messages typically contains a variety of system messages, not solely focused on security, while /var/log/auth.log is more commonly found in Debian-based systems rather than Red Hat distributions. Additionally, /var/log/secure.log is not a standard log file in Red Hat systems. Thus, /var/log/secure remains the most pertinent choice for the context of security and authentication logging.