--- /dev/null
+#
+# /etc/pam.d/common-auth - authentication settings common to all services
+#
+# This file is included from other service-specific PAM config files,
+# and should contain a list of the authentication modules that define
+# the central authentication scheme for use on the system
+# (e.g., /etc/shadow, LDAP, Kerberos, etc.). The default is to use the
+# traditional Unix authentication mechanisms.
+
+# here are the per-package modules (the "Primary" block)
+auth [success=1 default=ignore] pam_unix.so nullok_secure
+# here's the fallback if no module succeeds
+auth requisite pam_deny.so
+# prime the stack with a positive return value if there isn't one already;
+# this avoids us returning an error just because nothing sets a success code
+# since the modules above will each just jump around
+auth required pam_permit.so
+# and here are more per-package modules (the "Additional" block)