TCP Wrappers Release Notes

What’s in This Version
TCP Wrapper Features
Chapter 110
NOTE If the above entry is specified without the absolute path of
telnetd (/usr/lbin/telnetd), tcpd looks for the telnetd binary in
/usr/lbin/wrapper directory.
2. In order to monitor the access to a service, move the original
service daemon to the /usr/lbin/wrapper directory and move tcpd
in place of the original service daemon. No changes are required
to the /etc/inetd.conf file.
The following commands run in the command line, describe how
to enable the ftp service with tcpd:
# mkdir /usr/lbin/wrapper
# mv /usr/lbin/ftpd /usr/lbin/wrapper
# cp tcpd /usr/lbin/ftpd
Whenever any ftp service request comes in, inetd will spawn
/usr/lbin/ftpd which is actually the tcpd.Then tcpd performs
some access control checks before invoking the ftpd binary in
/usr/lbin/wrapper directory.
NOTE You can perform either of these steps to use tcpd.
Refer to tcpd(1M) and tcpd.conf(4) man pages for more
information on configuration.
• libwrap.a
The libwrap.a library provides a set of APIs for stand-alone
applications to enforce host access control based on /etc/hosts.allow
and /etc/hosts.deny files. The APIs implement a rule-based access
control language with optional shell commands that are executed
when a rule fires.
In order to enforce the host access control in a stand-alone daemon, it
has to include the tcpd.h header file and link with libwrap.a. This
library includes the following APIs:
— request_init()