I want to restrict network access to my server. This can be
          done through /etc/hosts.deny and /etc/hosts.allow on Unixware 7,
          but these files don't exist on Openserver.  The hosts.equiv man
          page says this file can be used for this purpose if NIS is
          configured with netgroups, but my system is not using NIS.

          Openserver does not have built-in support for /etc/hosts.deny and
          /etc/hosts.allow and the hosts.equiv file can only be used to
          deny access to other hosts if the system is running NIS and has
          netgroups defined.

          The hosts.deny and hosts.allow functionality is available through
          unsupported software called "TCP Wrappers", which allows you to
          control access to network services on your systems. For more
          information about TCP Wrappers,  you can access the SCO Secure
          Technologies Group web site at the following URL:

                http://www.sco.com/security

          This site also reports the latest security vulnerabilities and
          the fixes that are available for these.

          You can download TCP Wrappers for OpenServer at

                ftp://stage.sco.com/TLS/tls076a.tcp_wrappers.tar.Z
                ftp://stage.sco.com/TLS/tls076a.ltr

          This, and other various security tools and libraries can be
          downloaded on an unsupported basis from SCO's ftp site.