A security tool which acts as a wrapper for TCP daemons
ftp://ftp.porcupine.org/pub/security/index.html

The tcp_wrappers package provides small daemon programs which can
monitor and filter incoming requests for systat, finger, FTP, telnet,
rlogin, rsh, exec, tftp, talk and other network services.

Install the tcp_wrappers program if you need a security tool for
filtering incoming network services requests.

This version also supports IPv6.