CentOS 7 默认是使用Firewall作为防火墙，这里我们把它改为我们熟悉的iptables！
[root@Centos7 ~]# iptables -vnL #看着很不舒服，改为我们习惯的iptables Chain INPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 394 34135 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 82 8322 INPUT_direct all -- * * 0.0.0.0/0 0.0.0.0/0 82 8322 INPUT_ZONES_SOURCE all -- * * 0.0.0.0/0 0.0.0.0/0 82 8322 INPUT_ZONES all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 80 8218 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 0 0 FORWARD_direct all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 FORWARD_IN_ZONES_SOURCE all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 FORWARD_IN_ZONES all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 FORWARD_OUT_ZONES_SOURCE all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 FORWARD_OUT_ZONES all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited Chain OUTPUT (policy ACCEPT 41 packets, 5963 bytes) pkts bytes target prot opt in out source destination 331 35720 OUTPUT_direct all -- * * 0.0.0.0/0 0.0.0.0/0 Chain FORWARD_IN_ZONES (1 references) pkts bytes target prot opt in out source destination 0 0 FWDI_public all -- eno16777728 * 0.0.0.0/0 0.0.0.0/0 [goto] 0 0 FWDI_public all -- + * 0.0.0.0/0 0.0.0.0/0 [goto] Chain FORWARD_IN_ZONES_SOURCE (1 references) pkts bytes target prot opt in out source destination Chain FORWARD_OUT_ZONES (1 references) pkts bytes target prot opt in out source destination 0 0 FWDO_public all -- * eno16777728 0.0.0.0/0 0.0.0.0/0 [goto] 0 0 FWDO_public all -- * + 0.0.0.0/0 0.0.0.0/0 [goto] Chain FORWARD_OUT_ZONES_SOURCE (1 references) pkts bytes target prot opt in out source destination Chain FORWARD_direct (1 references) pkts bytes target prot opt in out source destination Chain FWDI_public (2 references) pkts bytes target prot opt in out source destination 0 0 FWDI_public_log all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 FWDI_public_deny all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 FWDI_public_allow all -- * * 0.0.0.0/0 0.0.0.0/0 Chain FWDI_public_allow (1 references) pkts bytes target prot opt in out source destination Chain FWDI_public_deny (1 references) pkts bytes target prot opt in out source destination Chain FWDI_public_log (1 references) pkts bytes target prot opt in out source destination Chain FWDO_public (2 references) pkts bytes target prot opt in out source destination 0 0 FWDO_public_log all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 FWDO_public_deny all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 FWDO_public_allow all -- * * 0.0.0.0/0 0.0.0.0/0 Chain FWDO_public_allow (1 references) pkts bytes target prot opt in out source destination Chain FWDO_public_deny (1 references) pkts bytes target prot opt in out source destination Chain FWDO_public_log (1 references) pkts bytes target prot opt in out source destination Chain INPUT_ZONES (1 references) pkts bytes target prot opt in out source destination 1 52 IN_public all -- eno16777728 * 0.0.0.0/0 0.0.0.0/0 [goto] 0 0 IN_public all -- + * 0.0.0.0/0 0.0.0.0/0 [goto] Chain INPUT_ZONES_SOURCE (1 references) pkts bytes target prot opt in out source destination Chain INPUT_direct (1 references) pkts bytes target prot opt in out source destination Chain IN_public (2 references) pkts bytes target prot opt in out source destination 82 8322 IN_public_log all -- * * 0.0.0.0/0 0.0.0.0/0 82 8322 IN_public_deny all -- * * 0.0.0.0/0 0.0.0.0/0 82 8322 IN_public_allow all -- * * 0.0.0.0/0 0.0.0.0/0 Chain IN_public_allow (1 references) pkts bytes target prot opt in out source destination 2 104 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22 ctstate NEW Chain IN_public_deny (1 references) pkts bytes target prot opt in out source destination Chain IN_public_log (1 references) pkts bytes target prot opt in out source destination Chain OUTPUT_direct (1 references) pkts bytes target prot opt in out source destination [root@Centos7 ~]# yum -y install iptables #安装iptables，基本上都是存在的 [root@Centos7 ~]# yum -y install iptables-services #安装iptables-services服务 [root@Centos7 ~]# systemctl stop firewalld.service #停止firealld服务 [root@Centos7 ~]# systemctl disable firewalld.service #禁止firealld服务自动启动 Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service. Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service. [root@Centos7 ~]# systemctl enable iptables.service #开启iptables自动启动 Created symlink from /etc/systemd/system/basic.target.wants/iptables.service to /usr/lib/systemd/system/iptables.service. [root@Centos7 ~]# systemctl start iptables.service #开启iptables服务 [root@Centos7 ~]# iptables -vnL #使用iptables查看，胡三汉回来了！~ Chain INPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination [root@Centos7 ~]# iptables-save #加载配置文件的规则 # Generated by iptables-save v1.4.21 on Sun Oct 23 02:34:48 2016 *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [121:22068] -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT # Completed on Sun Oct 23 02:34:48 2016 [root@Centos7 ~]# iptables -vnL #查看状态 Chain INPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 179 13428 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited Chain OUTPUT (policy ACCEPT 135 packets, 23948 bytes) pkts bytes target prot opt in out source destination [root@Centos7 ~]# iptables -F #清空规则 [root@Centos7 ~]# iptables-save #保持规则 # Generated by iptables-save v1.4.21 on Sun Oct 23 02:35:05 2016 *filter :INPUT ACCEPT [14:1096] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [11:1156] COMMIT # Completed on Sun Oct 23 02:35:05 2016 [root@Centos7 ~]# service iptables save #也可以使用这个保持规则 iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ] [root@Centos7 ~]#