The module name provides PAM the name of the pluggable module containing the specified module interface. Under older versions of Red Hat Enterprise Linux, the full path to the module was provided within the PAM configuration file, such as
/lib/security/pam_stack.so. However, since the advent of multilib systems, which store 64-bit PAM modules within the
/lib64/security/ directory, the directory name is omitted because the application is linked to the appropriate version of
libpam, which can locate the correct version of the module.