kazulog@sv1:~$ cat /etc/os-release | head -2
PRETTY_NAME="Ubuntu 26.04 LTS"
NAME="Ubuntu"
kazulog@sv1:~$ grep -n telnet /etc/inetd.conf
23:telnet	stream	tcp	nowait	root	/usr/sbin/tcpd	/usr/sbin/telnetd
kazulog@sv1:~$ cat /etc/hosts.deny
# /etc/hosts.deny: list of hosts that are _not_ allowed to access the system.
#                  See the manual pages hosts_access(5) and hosts_options(5).
#
# Example:    ALL: some.host.name, .some.domain
#             ALL EXCEPT in.fingerd: other.host.name, .other.domain
#
# If you're going to protect the portmapper use the name "rpcbind" for the
# daemon name. See rpcbind(8) and rpc.mountd(8) for further information.
#
# The PARANOID wildcard matches any host whose name does not match its
# address.
#
# You may wish to enable this to ensure any programs that don't
# validate looked up hostnames still leave understandable logs. In past
# versions of Debian this has been the default.
# ALL: PARANOID
telnetd: 192.168.100.20
kazulog@sv1:~$ systemctl is-enabled inetutils-inetd; systemctl is-active inetutils-inetd
enabled
active
kazulog@sv1:~$ sudo ss -tlnp 'sport = :23'
State              Recv-Q             Send-Q                          Local Address:Port                           Peer Address:Port             Process
LISTEN             0                  10                                    0.0.0.0:23                                  0.0.0.0:*                 users:(("inetutils-inetd",pid=3120,fd=4))             
kazulog@sv1:~$ dpkg -l | grep -E "inetutils|tcpd|update-inetd" | cat
ii  inetutils-inetd                         2:2.7-2ubuntu1.1                           amd64        internet super server
ii  inetutils-telnet                        2:2.7-2ubuntu1.1                           amd64        telnet client
ii  inetutils-telnetd                       2:2.7-2ubuntu1.1                           amd64        telnet server
ii  tcpd                                    7.6.q-36build2                             amd64        Wietse Venema's TCP wrapper utilities
ii  tcpdump                                 4.99.6-1                                   amd64        command-line network traffic analyzer
ii  telnet                                  0.17+2.7-2ubuntu1.1                        all          transitional dummy package for inetutils-telnet default switch
ii  update-inetd                            4.54build1                                 all          inetd configuration file updater