How to use PAM for security of a dedicated server with processes but without multiple users?

PAM (Pluggable Authentication Modules) is a flexible authentication mechanism in Linux that allows security configuration without changing applications.

For a dedicated server with processes and a minimal number of users, PAM can be used as follows:

• Configure PAM modules to restrict access to processes and services, for example, using pam_limits to limit resources.
• Use pam_tally2 or pam_faillock to block login attempts in case of suspicious activity.
• Restrict access to ssh and other services via pam_access, setting rules based on IP, time, or users.
• For processes launched by system users, configure pam_namespace to isolate the environment.
• If there are few or no users, configure PAM so that authentication occurs through keys or certificates, excluding passwords.

Thus, PAM allows flexible management of security policies, even with few users, providing access control and protection against unauthorized use.