You can download a copy of TCP_wrappers from:
ftp://ftp.win.tue.nl/pub/security/
or
ftp://ftp.cert.org/pub/tools/tcp_wrappers/
The latest version as of this writing is 7.6. To install the wrappers, unpack the compressed tar file in a convenient source directory, as in:
cd /usr/local/src tar xzvf \ /directory/tcp_wrappers_7.6.tar.gz cd tcp_wrappers_7.6
Of course, you should read the README file before compiling and installing.
Wietse Venema describes two ways to install TCP_wrappers—the “easy” configuration and the “advanced” configuration. The easy configuration involves moving all your network daemons to another directory and replacing them with copies of the tcpd wrapper program. The advanced configuration leaves all the daemons in their usual places and involves editing the /etc/inetd.conf file to call the TCP_wrapper tcpd instead of the daemon.
With all due respect to Dr. Venema, I find the “advanced” configuration easier in practice. As noted by Garfinkel & Simpson, the advanced configuration also has the advantage of documenting exactly how each network service is invoked in one file, /etc/inetd.conf.
How you install TCP_wrappers on your own system is entirely up to you, but I strongly urge you to read all the available documentation and man pages first.