How to open all ports and allow all connections and connections in Ubuntu Server?

Question

ubuntu

Friends, please help me to solve this problem.

Answer 1

If the server is at home, behind a router, then simply forward all connections incoming to the server's local address.
If the server is hosted, then you don’t need to open anything if you didn’t close it yourself. And if closed, then open in the same place where they closed.
What makes you think that the ports are closed?

Answer 2

Turn off iptables firewall

Answer 3

By default, everything is allowed.