The pam.conf file in this example has the following contents for rlogin services:
# Authentication management ... # rlogin service rlogin auth sufficient pam_rhosts_auth.so.1 rlogin auth requisite pam_authtok_get.so.1 rlogin auth required pam_dhkeys.so.1 rlogin auth required pam_unix_auth.so.1 ...
When the rlogin service requests authentication, libpam first executes the pam_rhosts_auth(5) module. The control flag is set to sufficient for the pam_rhosts_auth module. If the pam_rhosts_auth module is able to authenticate the user, then processing stops and success is returned to the application.
If the pam_rhosts_auth module fails to authenticate the user, then the next PAM module, pam_authtok_get(5) is executed. The control flag for this module is set to requisite. If pam_authtok_get fails, then the authentication process ends and the failure is returned to rlogin.
If pam_authtok_get succeeds, then the next two modules, pam_dhkeys(5) and pam_unix_auth(5), are executed. Both modules have the associated control flags that are set to required so that the process continues regardless of whether an individual failure is returned. After pam_unix_auth is executed, no modules for rlogin authentication remain. At this point, if either pam_dhkeys or pam_unix_auth has returned a failure, the user is denied access through rlogin.