IPv6 Network Administration

Inetd/TCP Wrappers

Inetd, a daemon that manages many smaller network services, is available on most Unix systems. Traditionally, these services have included diagnostic capabilities like generating and discarding data, management of Unix services such as telnet, FTP, and finger, and sometimes slightly more heavyweight applications such as IMAP and its encrypted relatives.

Most of these services have obvious extensions into the IPv6 world, and so inetd also needs to be changed. AIX, FreeBSD, Tru64 and Solaris all provide an IPv6-capable version of inetd. Some Linux distributions provide a version of inetd, while others use a variant of inetd called xinetd, which also supports IPv6. OS X provides inetd and xinetd, though only xinetd supports IPv6. If your system's inetd does not support IPv6, then you can get xinetd from http://www.xinetd.org/.

The services inetd provides are configured in /etc/inetd.conf. In the traditional format of this file, the third field is either tcp or udp, to indicate the sort of service inetd should run. This has been extended to also allow tcp6 or udp6, indicating that IPv6 services are provided. For example, the following would configure inetd to listen for telnet connections over IPv6 and IPv4.

telnet stream tcp  nowait  root  /usr/libexec/telnetd  telnetd
telnet stream tcp6 nowait  root  /usr/libexec/telnetd  telnetd

There are several points to note about this setup. First, it is usually not necessary to configure a separate daemon for IPv4 and IPv6, as an IPv6 ...