1.  Linux系统：Red Hat Enterprise Linux Server release 6.5 (Santiago)

临时关闭防火墙命令：

service iptables stop

service ip6tables stop

永久关闭防火墙命令：

chkconfig iptables off

chkconfig ip6tables off

查看防火墙状态命令：

service iptables status

[root@hadoop ~]# cat /etc/redhat-release

Red Hat Enterprise Linux Server release6.5(Santiago)

[root@hadoop~]# service iptables stop

iptables: Setting chains to policy ACCEPT: filter [ OK ]

iptables: Flushing firewall rules: [ OK ]

iptables: Unloading modules: [ OK ]

[root@hadoop~]# service ip6tables stop

ip6tables: Setting chains to policy ACCEPT: filter [ OK ]

ip6tables: Flushing firewall rules: [ OK ]

ip6tables: Unloading modules: [ OK ]

[root@hadoop~]# service iptables status

iptables: Firewallisnot running.

[root@hadoop~]# service ip6tables status

ip6tables: Firewallisnot running.

[root@hadoop~]# chkconfig iptables off

[root@hadoop~]# chkconfig ip6tables off

2.  linux系统：CentOS Linux release 7.5.1804 (Core)

前面说的几个命令，我在centos 7上用着都失效了。网上说，centos从7开始默认用的是firewalld，这个是基于iptables的，虽然有iptables的核心，但是iptables的服务是没安装的。所以你只要停止firewalld服务即可

[root@hadoop ~]# sudo systemctl stop firewalld.service &&sudo systemctl disable firewalld.service

Removed symlink/etc/systemd/system/multi-user.target.wants/firewalld.service.

Removed symlink/etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

如果你要改用iptables的话，需要安装iptables服务，并对命令做一些修改

[root@hadoop ~]# service iptables stop #命令失效

Redirecting to/bin/systemctl stop iptables.service

Failed to stop iptables.service: Unit iptables.service not loaded.

[root@hadoop~]# yum install iptables-services

[root@hadoop~]# /bin/systemctl stop iptables.service

[root@hadoop~]# /bin/systemctl stop ip6tables.service

永久关闭防火墙

[root@hadoop ~]# chkconfig iptables off #命令失效

Note: Forwarding request to'systemctl disable iptables.service'.

[root@hadoop~]# systemctl disable iptables.service

[root@hadoop~]# systemctl disable ip6tables.service

查看防火墙是否关闭

[root@hadoop ~]# firewall-cmd --state

not running

总结：centos 7系统关闭防火墙有2种方式：

方式1：

关闭防火墙：systemctl stop firewalld.service

永久关闭防火墙：systemctl disable firewalld.service

方式2：

首先安装iptables服务：yum install iptables-services

关闭防火墙：/bin/systemctl stop iptables.service && /bin/systemctl stop ip6tables.service

永久关闭防火墙：systemctl disable iptables.service && systemctl disable ip6tables.service

查看防火墙是否关闭：firewall-cmd --state