1.centos7自带了firewall,而不是iptables:

　　关闭firewall:

service firewalld stop

　　或者:

systemctl stop firewalld

　　禁止firewall:

systemctl mask firewalld

　　下面是替换成iptables操作:

yum -y install iptables-services

　　开机启动:

systemctl enable iptables

　　启动iptables:

systemctl start iptables

that'it...