I’m a novice in Ubuntu, so I can not understand why the port does not open and how it is still done. Tell me, please!

I tried to open the port in iptables, but, as I understood, IPTables serve to manage firewall UFW, and when entering the Sudo UFW Status command, I get the answer:

sudo: ufw: Command Not Found 

as in this case open port? The google advised me only IPTables.

Just in case I will give the output of the Netstat -an team | Grep Listen

tcp 0 0 0 127.0.0.1:25 0.0.0.0:* listentcp 0 0 127.0.0.1:953 0.0.0.0:* ListentCp 0 0 0 127.0.0.1:587 0.0.0.0:* ListentCP 0 0 0.0.0.0:80 0.0.0.0:* ListentCP 0 0 5.231.61.235:53 0.0.0.0: * Listentcp 0 0 0 127.0.0.2:53 0.0.0.0:* ListentCp 0 0 0 127.0.0.1:53 0.0.0:* ListentCp 0 0 0.0.0.0:22 0.0.0.0:* ListentCp 0 0 0 127.0.0.1:631 0.0. 0.0: * listentcp6 0 0 :: 1: 953 :::: * listentcp6 0 0 ::::::::::: listentcp6 0 0 0 ::: 22 ::: * ListentCP6 0 0 :: 1 : 631 ::: * ListenUnix 2 [ACC] Stream Listening 3215411995 /var/run/cups/cups.sockunix 2 [ACC] Stream Listening 3215409707 / VAR / RUN / AVAHI-Daemon / Socketunix 2 [ACC] Stream Listening 3215403381 @ / COM / UBuntu / Upstartunix 2 [ACC] Stream Listening 3215406175 / VAR / RUN / DBUS / System_Bus_SocketUnix 2 [ACC] Stream Listening 3215553140 / Var / Run / Sendmail / MTA / SMControlunix 2 [ACC] Stream Listening 3215421071 / VAR / RUN / ACPID .socketunix 2 [ACC] SeqPacket Listening 3215405745 / RUN / UDEV / Controlunix 2 [ACC] Stream Listening 3215427067 / VAR / RUN / SASLAUTHD / MUX 

That is, it seems like the 53rd port open … how else to open ports?

Answer 1, Authority 100%

Your listing is not open ports, but the output of that which ports listen.

If you want to use the TCP port 53 using the IPTABLES utility:

IPTABLES -I INPUT -P TCP -M TCP --DPORT 53 -J Accept 

Answer 2

If it comes exactly about Ubuntu, and after installing it, no additional actions have been taken over the firewall, it has all the ports

Answer 3

Install the UFW utility:

apt-get install ufw