The ftpd can be run as the main ftpd on the machine as a replacement for
the standard one. It's only really useful if the machine does not run a
normal ftpd.

To install using this method.
First, make sure you undefined STANDALONE and changed RUNAS_USERNAME 
in security.h
You should edit /etc/inetd.conf (or equivalent file) and change the line 
already there which relates to ftpd to the following. (this is specifically
taken from the linux machine on which I tested this and may not be
*exactly* right for your machine.)

ftp	stream	tcp	nowait	root	/usr/sbin/tcpd	/home/mud/ftpd -l
                                                        
Where /home/mud/ftpd should be replaced with the pathname of the ftpd
binary and the -l can be replaced with whatever options you prefer. 
Remember that the ftpd will be running with root privileges, although it
will switch to the correct username (defined in security.h) while it does
not need the root uid. You may want to place the binary in a secure 
directory, therefore, to avoid the user replacing it with another program
and thereby gaining full access to the machine AS ROOT.
The ftpd binary need only be executable by root.

