yum install firewalld (7은 이미 깔려 있을겁니다.)
service firewalld start 를 합니다.
systemctl enable firewalld (firewalld 적용)
gedit /etc/firewalld/zones/public.xml
아래 내용 추가 및 수정 (허용 포트 오픈)

<?xml version="1.0" encoding="utf-8"?>
<zone>
  <short>Public</short>
  <description>For use in public areas. You do not trust the other computers on networks to not harm your computer. Only selected incoming connections are accepted.</description>
  <service name="ftp"/>
  <service name="mdns"/>
  <service name="http"/>
  <service name="mysql"/>
  <service name="dns"/>
  <service name="smtp"/>
  <service name="ssh"/>
  <service name="https"/>
  <port protocol="tcp" port="110"/>
  <port protocol="tcp" port="443"/>
  <port protocol="tcp" port="21"/>
  <port protocol="tcp" port="80"/>
  <port protocol="udp" port="53"/>
  <port protocol="tcp" port="587"/>
  <port protocol="tcp" port="25"/>
  <port protocol="tcp" port="1024"/>
  <port protocol="tcp" port="20"/>
  <port protocol="tcp" port="993"/>
  <port protocol="tcp" port="10000"/>
  <port protocol="tcp" port="143"/>
  <port protocol="tcp" port="3306"/>
  <port protocol="tcp" port="2030"/>
  <port protocol="udp" port="3306"/>
  <port protocol="tcp" port="53"/>
  <port protocol="tcp" port="60"/>
  <port protocol="tcp" port="995"/>
  <port protocol="udp" port="80"/>
  <port protocol="tcp" port="22"/>
</zone>

port는 안적으셔도 될 것 같구 service 들만 넣으셔도 될듯 합니다.
그래도 모르니 일단 적어 놓습니다.
service firewalld restart (터미널에서)
포트를 열었는데도 접속이 안되시면 공유기 포트 포워딩 하세요.