Detailed modification of Linux system firewall

In Linux, you can modify the firewall configuration by modifying the file. How can you modify the configuration to improve the protection effect or achieve your desired purpose? I believe many administrators who are new to Linux must be curious. Next we will introduce how to modify the Linux system firewall.

To modify the firewall configuration, You need to modify the/etc/sysconfig/iptables file. If you want to open a port, add one in it.

-A RH-Firewall-1-INPUT-m state -- state NEW-m tcp-p tcp -- dport 1521-j ACCEPT

1521 indicates the port number to be opened, and then restart the Firewall Service in linux.

Command to stop/start the Firewall Service:

Run

Service iptables stop -- stop

Service iptables start -- start

(The service command is located in/sbin)

Firewall Rules can be activated only when the iptables service is running. To manually start the service, run the following command:

/Sbin rvice iptables restart

To ensure that it is started during system boot, run the following command:

/Sbin/chkconfig -- level 345 iptables on

The ipchains service cannot run with the iptables service at the same time. To disable the ipchains service, run the following command:

/Sbin/chkconfig -- level 345 ipchains off

The modification of the Linux system firewall also needs to be designed according to personalized requirements. administrators should understand it on their own.

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