I am new to Ubuntu (I installed it just 4 days ago) and want to know something about network ports: which port is opened or closed?
I read many answers about this field, but I am unable to understand how to identify ports (opened or closed). When I run this command
sudo netstat -ntlup I get the following output:
Could you tell me, which port is open or at risk? How to close open ports using firewall rules?