telnet em 16.04

Eu tenho um sistema em execução xeniale preciso verificar se determinadas portas estão abertas, por 127.0.0.1isso decidi instalar telnetpara simplesmente tentar conectar nessa porta em particular.

I've tried the following:
ron@regDesktopHome:/etc/ssl/certs$ sudo apt-get install telnetd -y
Reading package lists... Done
Building dependency tree       
Reading state information... Done
telnetd is already the newest version (0.17-40).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
ron@regDesktopHome:/etc/ssl/certs$ sudo systemctl status inetd
● xinetd.service - LSB: Starts or stops the xinetd daemon.
   Loaded: loaded (/etc/init.d/xinetd; bad; vendor preset: enabled)
   Active: active (running) since Sun 2019-06-09 18:02:19 PDT; 10min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 2050 ExecStop=/etc/init.d/xinetd stop (code=exited, status=0/SUCCESS)
  Process: 2062 ExecStart=/etc/init.d/xinetd start (code=exited, status=0/SUCCESS)
    Tasks: 1
   Memory: 192.0K
      CPU: 22ms
   CGroup: /system.slice/xinetd.service
           └─2080 /usr/sbin/xinetd -pidfile /run/xinetd.pid -stayalive -inetd_compat -inetd_ipv6

Jun 09 18:02:19 regDesktopHome xinetd[2080]: removing daytime
Jun 09 18:02:19 regDesktopHome xinetd[2080]: removing daytime
Jun 09 18:02:19 regDesktopHome xinetd[2080]: removing discard
Jun 09 18:02:19 regDesktopHome xinetd[2080]: removing discard
Jun 09 18:02:19 regDesktopHome xinetd[2080]: removing echo
Jun 09 18:02:19 regDesktopHome xinetd[2080]: removing echo
Jun 09 18:02:19 regDesktopHome xinetd[2080]: removing time
Jun 09 18:02:19 regDesktopHome xinetd[2080]: removing time
Jun 09 18:02:19 regDesktopHome xinetd[2080]: xinetd Version 2.3.15 started with libwrap loadavg options compiled in.
Jun 09 18:02:19 regDesktopHome xinetd[2080]: Started working: 1 available service
ron@regDesktopHome:/etc/ssl/certs$ telnet 127.0.0.1
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused
ron@regDesktopHome:/etc/ssl/certs$ 

O que há aqui, por que não consigo me conectar localhost telnet?

nmape lsofsão apenas duas das melhores maneiras de verificar uma porta.

Para ver as portas 1-100,

sudo nmap -p1-100 localhost

Para ver qual processo tem porta 80aberta,

lsof -i tcp:80

Claro, leia man nmap;man lsof.