How to open all ports in CentOS 7?

To open all ports on CentOS 7, you can follow these steps:

1. Log in to the root account or an account with sudo privileges on the CentOS 7 server.
2. Open the firewall configuration file iptables or firewalld (depending on the firewall you are using).
3. If you are using iptables, edit the /etc/sysconfig/iptables file.
4. If you are using firewalld, run the following commands to open the firewall configuration tool:
   firewall-cmd –zone=public –permanent –add-port=1-65535/tcp
   firewall-cmd –zone=public –permanent –add-port=1-65535/udp
5. Save and close the configuration file.
6. Restart the firewall to apply the changes.
7. If you are using iptables, then run the following commands: systemctl restart iptables, systemctl enable iptables.
8. If you are using firewalld, you should run the following commands: systemctl restart firewalld and systemctl enable firewalld.

Now all ports on CentOS 7 have been opened. Please note that doing so will lower the security of the server, as all ports are open.