How does the CentOS system open a specified port in iptables firewall?

After CentOS is installed, only port 22 is enabled by default. if you want to open other ports, you need to open the required ports. For example, open the default port 80 for http edit iptablesvi/etc/sysconfig/iptables add-ARH-Firewall-1-INPUT-mstate -- stateNEW-mtcp-ptcp -- dport3001-jACCE CentOS installed, by default only port 22 is opened, to open other ports, open the required ports.

For example, open the default http port 80.

Edit IptablesVi/etc/sysconfig/ Iptables

Add-A RH-Firewall-1-INPUT-m state -- state NEW-m tcp-p tcp -- dport 3001-j ACCEPT

Restart the service/sbin/service iptables restart

Check whether/sbin/iptables-L-n is enabled on the port.