The old-school way to do this is to install inetd, ensure it gets started up, and uncomment the line in its config-file (/etc/inetd.conf ?) for telnet.
Setting up an ftp chroot area is painful. If you're using cleartext passwords (telnet) anyway, I'd set up rlogin/rsh, and use rcp. Same story: /etc/inetd.conf, or whatever Debian replaced that with. Assuming Ultrix-11 has rsh/rcp, that is.
