1. $ sudo netstat -tulpn
    2. Active Internet connections (only servers)
    3. Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
    4. tcp        0      0 127.0.0.53:53           0.0.0.0:*               LISTEN      860/systemd-resolve
    5. tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      3354153/sshd: /usr/
    6. tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/init
    7. tcp        0      0 0.0.0.0:8081            0.0.0.0:*               LISTEN      3602297/docker-prox
    8. tcp6       0      0 :::21                   :::*                    LISTEN      3714899/vsftpd
    9. tcp6       0      0 :::22                   :::*                    LISTEN      3354153/sshd: /usr/
    10. tcp6       0      0 :::111                  :::*                    LISTEN      1/init
    11. udp        0      0 127.0.0.53:53           0.0.0.0:*                           860/systemd-resolve
    12. udp        0      0 10.0.4.16:68            0.0.0.0:*                           858/systemd-network
    13. udp        0      0 0.0.0.0:111             0.0.0.0:*                           1/init
    14. udp        0      0 172.17.0.1:123          0.0.0.0:*                           945/ntpd
    15. udp        0      0 10.0.4.16:123           0.0.0.0:*                           945/ntpd
    16. udp        0      0 127.0.0.1:123           0.0.0.0:*                           945/ntpd
    17. udp        0      0 0.0.0.0:123             0.0.0.0:*                           945/ntpd
    18. udp6       0      0 :::111                  :::*                                1/init
    19. udp6       0      0 fe80::b482:dfff:fe8:123 :::*                                945/ntpd
    20. udp6       0      0 fe80::42:2ff:fe02:3:123 :::*                                945/ntpd
    21. udp6       0      0 fe80::5054:ff:fe06::123 :::*                                945/ntpd
    22. udp6       0      0 ::1:123                 :::*                                945/ntpd
    23. udp6       0      0 :::123                  :::*                                945/ntpd