To enable telnetd in Ubuntu first install telnetd with
apt-get install telnetd
Once completed edit /etc/inetd.conf and add
telnet stream tcp nowait root /usr/sbin/tcpd in.telnetd
When completed restart inetd with /etc/init.d/openbsd-inetd restart
InterServer recommend using SSH over telnet.
You can skip to the end and leave a response. Pinging is currently not allowed.