After installing leafnode, I read in /usr/local/share/doc/leafnode/INSTALL
11a.ONLY WHEN USING INETD (Beware, many systems ship xinetd nowadays, see
section 11b below instead.)
(as root) Edit /etc/inetd.conf so that $(BINDIR)/leafnode is executed for
incoming NNTP connections. Here is my inetd.conf line (insert it at the
leftmost column, without leading spaces!):
nntp stream tcp nowait news /usr/sbin/tcpd /usr/local/sbin/leafnode
This starts leafnode for all connections on the nntp port, subject to
/etc/hosts.allow and /etc/hosts.deny screening. If you don't have
/usr/sbin/tcpd, fetch the tcp_wrappers package and install it.
Using leafnode without tcpd is not supported and opens your computer to
abuse (even happens on modem lines that are only connected during the
fetch!)