24 个常用的 iptables 规则-工具盒子

iptables 是 Linux 系统自带防火墙，在 CentOS6 之前，系统都会默认安装，虽然到 CentOS7 之后，系统将防火墙换成了 firewalld，但经验丰富的运维人员还是倾向于 iptables。今天杜老师为大家分享 24 个常用的 iptables 规则！

设置默认的 Chain 策略 {#设置默认的-Chain-策略}

|---------------|---------------------------------------------------------------------------------| | 1 2 3 | iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT DROP |

阻止某个特定的 IP 地址 {#阻止某个特定的-IP-地址}

|-----------|-----------------------------------------------------| | 1 | iptables -A INPUT -s 192.168.1.0/24 -j DROP |

允许全部进来的 SSH {#允许全部进来的-SSH}

|-------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -i eth0 -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT |

允许某个特定网络进来的 SSH {#允许某个特定网络进来的-SSH}

|-------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -i eth0 -p tcp -s 192.168.1.0/24 --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT |

允许进来的 HTTP {#允许进来的-HTTP}

|-------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -i eth0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT |

多个端口允许进来的 SSH、HTTP 以及 HTTPS {#多个端口允许进来的-SSH、HTTP-以及-HTTPS}

|-------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -i eth0 -p tcp -m multiport --dports 22,80,443 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp -m multiport --sports 22,80,443 -m state --state ESTABLISHED -j ACCEPT |

允许出去的 SSH {#允许出去的-SSH}

|-------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A OUTPUT -o eth0 -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A INPUT -i eth0 -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT |

允许外出的 SSH，仅访问某个特定的网络 {#允许外出的-SSH，仅访问某个特定的网络}

|-------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A OUTPUT -o eth0 -p tcp -d 192.168.1.0/24 --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A INPUT -i eth0 -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT |

允许外出的 HTTPS {#允许外出的-HTTPS}

|-------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A OUTPUT -o eth0 -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A INPUT -i eth0 -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT |

对进来的 HTTPS 流量做负载均衡 {#对进来的-HTTPS-流量做负载均衡}

|---------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 3 | iptables -A PREROUTING -i eth0 -p tcp --dport 443 -m state --state NEW -m nth --counter 0 --every 3 --packet 0 -j DNAT --to-destination 192.168.1.1:443 iptables -A PREROUTING -i eth0 -p tcp --dport 443 -m state --state NEW -m nth --counter 0 --every 3 --packet 1 -j DNAT --to-destination 192.168.1.2:443 iptables -A PREROUTING -i eth0 -p tcp --dport 443 -m state --state NEW -m nth --counter 0 --every 3 --packet 2 -j DNAT --to-destination 192.168.1.3:443 |

内部向外部 Ping {#内部向外部-Ping}

|-------------|----------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT |

外部向内部 Ping {#外部向内部-Ping}

|-------------|----------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT iptables -A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT |

允许环回访问 {#允许环回访问}

|-------------|------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -i lo -j ACCEPT iptables -A OUTPUT -o lo -j ACCEPT |

允许 Packets 从内网访问外网 {#允许-Packets-从内网访问外网}

|-----------|-------------------------------------------------------| | 1 | iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT |

允许外出的 DNS {#允许外出的-DNS}

|-------------|----------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A OUTPUT -p udp -o eth0 --dport 53 -j ACCEPT iptables -A INPUT -p udp -i eth0 --sport 53 -j ACCEPT |

允许 NIS 的连接 {#允许-NIS-的连接}

|---------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 3 4 5 6 | iptables -A INPUT -p tcp --dport 111 -j ACCEPT iptables -A INPUT -p udp --dport 111 -j ACCEPT iptables -A INPUT -p tcp --dport 853 -j ACCEPT iptables -A INPUT -p udp --dport 853 -j ACCEPT iptables -A INPUT -p tcp --dport 850 -j ACCEPT iptables -A INPUT -p udp --dport 850 -j ACCEPT |

允许某个特定的网络 rsync 进入本机 {#允许某个特定的网络-rsync-进入本机}

|-------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -i eth0 -p tcp -s 192.168.1.0/24 --dport 873 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 873 -m state --state ESTABLISHED -j ACCEPT |

仅允许来自某个特定网络的 MySQL 的链接 {#仅允许来自某个特定网络的-MySQL-的链接}

|-------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -i eth0 -p tcp -s 192.168.1.0/24 --dport 3306 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 3306 -m state --state ESTABLISHED -j ACCEPT |

允许 Sendmail 或者 Postfix {#允许-Sendmail-或者-Postfix}

|-------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 | iptables -A INPUT -i eth0 -p tcp --dport 25 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 25 -m state --state ESTABLISHED -j ACCEPT |

允许 IMAP 以及 IMAPS {#允许-IMAP-以及-IMAPS}

|-----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 3 4 | iptables -A INPUT -i eth0 -p tcp --dport 143 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 143 -m state --state ESTABLISHED -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 993 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 993 -m state --state ESTABLISHED -j ACCEPT |

允许 POP3 以及 POP3S {#允许-POP3-以及-POP3S}

|-----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 3 4 | iptables -A INPUT -i eth0 -p tcp --dport 110 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 110 -m state --state ESTABLISHED -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 995 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport 995 -m state --state ESTABLISHED -j ACCEPT |

防止 Dos 的攻击 {#防止-Dos-的攻击}

|-----------|----------------------------------------------------------------------------------------------------| | 1 | iptables -A INPUT -p tcp --dport 80 -m limit --limit 25/minute --limit-burst 100 -j ACCEPT |

将 422 端口转发到 22 端口 {#将-422-端口转发到-22-端口}

为丢弃的包做日志 {#为丢弃的包做日志}

|-----------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 3 4 | iptables -N LOGGING iptables -A INPUT -j LOGGING iptables -A LOGGING -m limit --limit 2/min -j LOG --log-prefix "iptables packet: " --log-level 7 iptables -A LOGGING -j DROP |