It appears that Debian dropped netkit-telnet for netkit-telnet-ssl.
https://packages.debian.org/sid/telnet-ssl
> SSL telnet replaces normal telnet using SSL authentication and encryption. It interoperates with normal telnetd in both directions. It checks if the other side is also talking SSL, if not it falls back to normal telnet protocol.
It appears that Debian dropped netkit-telnet for netkit-telnet-ssl.
https:/ /packages. debian. org/sid/ telnet- ssl
> SSL telnet replaces normal telnet using SSL authentication and encryption. It interoperates with normal telnetd in both directions. It checks if the other side is also talking SSL, if not it falls back to normal telnet protocol.