The directory /etc/pam.d/ contains the PAM
configuration files for each PAM-aware application. In earlier versions
of PAM, the file /etc/pam.conf was used, but this
file is now deprecated and is only used if the
/etc/pam.d/ directory does not exist.
Each PAM-aware application or service
has a file within the /etc/pam.d/
directory. Each file within this directory bears the name
of the service for which it controls access.
It is up to the PAM-aware program to define its service name
and install its own PAM configuration file in the
/etc/pam.d/ directory. For example, the
login program defines its service name as
login and installs the /etc/pam.d/login
PAM configuration file.
