Those applications that require authentication can register at PAM using a service name. The name of the service is determined by the application at the initial call to the PAM library during the authentication process, which is a call to the library function pam_start. It is rare that the name can be set by the user in a configuration file. The Linux box has the following services:
pamela@pamela:~$ ls /etc/pam.d/
atd common-auth groupadd other useradd
charge common-pammount groupdel passwd userdel
chfn common-password groupmod ppp usermod
chsh common-session login su
common-account cron newusers sudoBesides the file names beginning with common, each file represents a service, and PAM will use a configuration file named as the service if the /etc/pam.d directory exists. If PAM is configured by the single file, /etc/pam.conf, the service name is written in the configuration file in the first column:
login auth required...