[CentOS 7] 방화벽 firewall-cmd 설치 실행

[root@localhost ~]# firewall-cmd
usage: see firewall-cmd man page
No option specified.

[root@localhost ~]# firewall-cmd --zone=public --permanent --add-port=21/tcp
FirewallD is not running


1. 작동여부 확인

1-1. 방법
[root@localhost ~]# systemctl status firewalld
* firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:firewalld(1)

1-2. 방법
[root@localhost ~]# firewall-cmd --state
not running


2. firewalld 설치확인
[root@localhost ~]# yum list installed firewalld
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: ftp.daumkakao.com
 * epel: ftp.riken.jp
 * extras: ftp.daumkakao.com
 * updates: ftp.daumkakao.com
 * webtatic: sp.repo.webtatic.com
Installed Packages
firewalld.noarch                       0.4.4.4-6.el7                       @base


3. 패키지 삭제
[root@localhost ~]# yum remove firewalld.noarch


4. firewall 설치
[root@localhost ~]# yum install firewalld


5. firewall 실행
[root@localhost my.cnf.d]# systemctl start firewalld


6. firewall 상태 확인
[root@localhost my.cnf.d]# systemctl status firewalld
* firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2018-01-30 17:12:19 KST; 4s ago
     Docs: man:firewalld(1)
 Main PID: 21620 (firewalld)
   CGroup: /system.slice/firewalld.service
           `-21620 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid



참고자료
https://www.certdepot.net/rhel7-get-started-firewalld/
https://www.liquidweb.com/kb/how-to-start-and-enable-firewalld-on-centos-7/