2019-08-12  2024-09-18    388 字  1 分钟

whereis iptables #查看系统是否安装防火墙可以看到:

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iptables: /sbin/iptables /usr/share/iptables /usr/share/man/man8/iptables.8.gz #表示已经安装iptables apt-get install iptables #如果默认没有安装,请运行此命令安装防火墙

iptables -L #查看防火墙配置信息,显示如下:

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Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination

vi /etc/iptables/rules.v4

添加以下内容(备注:80是指web服务器端口,3306是指MySQL数据库链接端口,22是指SSH远程管理端口.)

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*filter :INPUT DROP [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :syn-flood - [0:0] -A INPUT -i lo -j ACCEPT -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 443 -j ACCEPT -A INPUT -p icmp -m limit --limit 100/sec --limit-burst 100 -j ACCEPT -A INPUT -p icmp -m limit --limit 1/s --limit-burst 10 -j ACCEPT -A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j syn-flood -A INPUT -j REJECT --reject-with icmp-host-prohibited -A syn-flood -p tcp -m limit --limit 3/sec --limit-burst 6 -j RETURN -A syn-flood -j REJECT --reject-with icmp-port-unreachable COMMIT

iptables-restore < /etc/iptables/rules.v4 #使防火墙规则生效

vi /etc/network/if-pre-up.d/iptables #创建文件,添加以下内容,使防火墙开机启动

chmod +x /etc/network/if-pre-up.d/iptables #添加执行权限

iptables -L -n查看规则是否生效.

临时修改

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# 列出所有规则 iptables -nL --line-number # 将第三条规则改为ACCEPT iptables -R INPUT 3 -j ACCEPT