I followed these instructions but when doing telnet localhost or telnet localhost 23, getting unable to connect to remote host: connection refused.
I also shut down firewall: sudo ufw disable.
When doing sudo /etc/init.d/xinetd status I get active (running)
I can do telnet to the internet e.g. telnet google.com 80 (I know this is telnet client)
More information: version 18.04.1 TLS, running on Oracle VM VirtualBox.