[Linux 常見問題] How can i use iptables on Centos7?

Source From Here
Question
I installed CentOS 7 with minimal configuration (os + dev tools). I am trying to open 80 port for httpd service, but something wrong with my iptables service:

# ifconfig/sbin/service iptables save
bash: ifconfig/sbin/service: No such file or directory

# /sbin/service iptables save
The service command supports only basic LSB actions (start, stop, restart, try-restart, reload, force-reload, status). For other actions, please try to use systemctl.

# sudo service iptables status
Redirecting to /bin/systemctl status iptables.service
iptables.service
Loaded: not-found (Reason: No such file or directory)
Active: inactive (dead)

How-To
With RHEL 7 / CentOS 7, firewalld was introduced to manage iptables. IMHO, firewalld is more suited for workstations than for server environments. It is possible to go back to a more classic iptables setup. First, stop and mask the firewalld service:

# systemctl stop firewalld
# systemctl mask firewalld // Mask one or more unit files, as specified on the command line. This will link these units to /dev/null, making it impossible to start them.

Then, install the iptables-services package:

# yum install iptables-services

Enable the service at boot-time:

# systemctl enable iptables

Managing the service:

# systemctl [stop|start|restart] iptables

Saving your firewall rules can be done as follows:

# service iptables save
or
# /usr/libexec/iptables/iptables.init save