Linux firewall set Port method detailed

Linux itself has a firewall named "Iptables". The Dark One you said is the terminal. Enter the following command in the terminal to open the firewall:

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Chkconfig iptables on

If the firewall is closed, enter:

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Chkconfig iptables off

All two of these commands have to be restarted for the system to take effect.
You can use the service command if you do not want to take effect immediately by restarting the system. The disadvantage is that the settings will be lost when you reboot the system.

Firewall turned on:

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Service Iptables Start

To turn off the firewall:

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Service Iptables Stop

To set a switch on some ports in the firewall, modify the edit/etc/sysconfig/iptables file, such as SSH Port 22, which can be added as follows:

When the firewall is turned on, make the following settings, open the relevant port,

Modify the/etc/sysconfig/iptables file and add the following:

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-A rh-firewall-1-input-m state--state new-m tcp-p TCP--dport 80-j ACCEPT -A rh-firewall-1-input-m state--state new-m tcp-p TCP--dport 22-j ACCEPT

CentOS Linux firewall configuration and shutdown

Perform the "Setup" command to start the text mode configuration Utility, select "Firewall Configuration" in "Select a tool", then select the "Run Tool" button, the firewall configuration interface appears, set the security level to Disabled, and select OK.

or by command:

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#/sbin/iptables-i input-p tcp–dport 80-j ACCEPT #/sbin/iptables-i input-p tcp–dport 22-j ACCEPT #/etc/rc.d/init.d/iptables Save

After this reboot the computer, the firewall has opened 80 and 22 ports by default
You should also not reboot the computer here:

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#/etc/init.d/iptables restart

To turn off the Firewall service:

To view firewall information:

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#/etc/init.d/iptables status

To turn off the Firewall service:

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#/etc/ Init.d/iptables stop