The inetd server should be run at boot time by /etc/rc. It then listens for connections on certain internet sockets. When a connection is found on one of its sockets, it decides what service the socket corresponds to, and invokes a program to service the request. The server program is invoked with the service socket as its standard input, output and error descriptors. After the program is finished, inetd continues to listen on the socket.

To enable FTPD Open /etc/inetd.conf file and remove the hash from:

ftp stream tcp nowait root /usr/libexec/ftpd ftpd -l

Then restart inetd.conf

/etc/rc.d/inetd restart
or
/etc/rc.d/inetd onerestart

Or allow only 127.0.0.1 (localhost) to connect to your ftp server:

ftp stream tcp nowait root /usr/libexec/ftpd ftpd -l -D -a 127.0.0.1