TCP Wrappers can be gotten at ftp://ftp.porcupine.org/pub/security/
7. PAM (Pluggable Authentication Modules for Linux)
+Linux-PAM provides a flexible mechanism for authenticating
+users. PAM was invented by SUN Microsystems.
+
+Author: Andrew Morgan <morgan@linux.kernel.org>
+
Linux-PAM is a suite of shared libraries that enable the local system
administrator to choose how applications authenticate users.