转:25个常用的 Linux iptables 规则


一些常用的 Linux iptables 规则,请根据自己的具体需要再修改。

 

# 1. 删除所有现有规则

 

iptables -F

 

# 2. 设置默认的 chain 策略

 

iptables -P INPUT DROP

iptables -P FORWARD DROP

iptables -P OUTPUT DROP

 

# 3. 阻止某个特定的 IP 地址

 

#BLOCK_THIS_IP=”x.x.x.x”

#iptables -A INPUT -s “$BLOCK_THIS_IP” -j DRO

 

# 4. 允许全部进来的(incoming)SSH

 

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

 

# 5. 只允许某个特定网络进来的 SSH

 

#iptables -A INPUT -i eth0 -p tcp -s 192.168.200.0/24 –dport 22 -m state –state NEW,ESTABLISHED -j ACCEPT

#iptables -A OUTPUT -o eth0 -p tcp –sport 22 -m state –state ESTABLISHED -j ACCEPT

 

# 6. 允许进来的(incoming)HTTP

 

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

 

# 7. 多端口(允许进来的 SSH、HTTP 和 HTTPS)

 

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

 

# 8. 允许出去的(outgoing)SSH

 

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

 

# 9. 允许外出的(outgoing)SSH,但仅访问某个特定的网络

 

#iptables -A OUTPUT -o eth0 -p tcp -d 192.168.101.0/24 –dport 22 -m state –state NEW,ESTABLISHED -j ACCEPT

#iptables -A INPUT -i eth0 -p tcp –sport 22 -m state –state ESTABLISHED -j ACCEPT

 

# 10. 允许外出的(outgoing) HTTPS

 

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

 

# 11. 对进来的 HTTPS 流量做负载均衡

 

#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 192.168.1.101:443

#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 192.168.1.102:443

#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 192.168.1.103:443

 

# 12. 从内部向外部 Ping

 

iptables -A OUTPUT -p icmp –icmp-type echo-request -j ACCEPT

iptables -A INPUT -p icmp –icmp-type echo-reply -j ACCEPT

 

# 13. 从外部向内部 Ping

 

iptables -A INPUT -p icmp –icmp-type echo-request -j ACCEPT

iptables -A OUTPUT -p icmp –icmp-type echo-reply -j ACCEPT

 

# 14. 允许环回(loopback)访问

 

iptables -A INPUT -i lo -j ACCEPT

iptables -A OUTPUT -o lo -j ACCEPT

 

# 15. 允许 packets 从内网访问外网

 

# if eth1 is connected to external network (internet)

# if eth0 is connected to internal network (192.168.1.x)

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

 

# 16. 允许外出的  DNS

 

iptables -A OUTPUT -p udp -o eth0 –dport 53 -j ACCEPT

iptables -A INPUT -p udp -i eth0 –sport 53 -j ACCEPT

 

# 17. 允许 NIS 连接

 

# rpcinfo -p | grep ypbind ; This port is 853 and 850

#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

 

# 18. 允许某个特定网络 rsync 进入本机

 

#iptables -A INPUT -i eth0 -p tcp -s 192.168.101.0/24 –dport 873 -m state –state NEW,ESTABLISHED -j ACCEPT

#iptables -A OUTPUT -o eth0 -p tcp –sport 873 -m state –state ESTABLISHED -j ACCEPT

 

# 19. 仅允许来自某个特定网络的 MySQL 的链接

 

#iptables -A INPUT -i eth0 -p tcp -s 192.168.200.0/24 –dport 3306 -m state –state NEW,ESTABLISHED -j ACCEPT

#iptables -A OUTPUT -o eth0 -p tcp –sport 3306 -m state –state ESTABLISHED -j ACCEPT

 

# 20. 允许 Sendmail 或 Postfix

 

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

 

# 21. 允许 IMAP 和 IMAPS

 

#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

 

# 22. 允许 POP3 和 POP3S

 

#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

 

# 23. 防止 DoS 攻击

 

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

 

# 24. 设置 422 端口转发到 22 端口

 

#iptables -t nat -A PREROUTING -p tcp -d 192.168.102.37 –dport 422 -j DNAT –to 192.168.102.37:22

#iptables -A INPUT -i eth0 -p tcp –dport 422 -m state –state NEW,ESTABLISHED -j ACCEPT

#iptables -A OUTPUT -o eth0 -p tcp –sport 422 -m state –state ESTABLISHED -j ACCEPT

 

# 25. 为丢弃的包做日志(Log)

 

iptables -N LOGGING

iptables -A INPUT -j LOGGING

iptables -A LOGGING -m limit –limit 2/min -j LOG –log-prefix “IPTables Packet Dropped: ” –log-level 7

iptables -A LOGGING -j DROP

 

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