iptables脚本

#echo "Starting kerryhu-iptables rules..."
#!/bin/bash
#this is a common firewall created by 2010-3-27

#define some variable
IPT=/sbin/iptables
CONNECTION_TRACKING="1"
INTERNET="eth0"
CLASS_A="10.0.0.0/8"
CLASS_B="172.16.0.0/12"
CLASS_C="192.168.0.0/16"
CLASS_D_MULTICAST="224.0.0.0/4"
CLASS_E_RESERVED_NET="240.0.0.0/5"
BROADCAST_SRC="0.0.0.0"
BROADCAST_DEST="255.255.255.255"
LOOPBACK_INTERFACE="lo"

#Remove any existing rules
$IPT -F
$IPT -X

#setting default firewall policy
$IPT --policy OUTPUT ACCEPT
$IPT --policy FORWARD DROP
$IPT -P INPUT DROP


#stop firewall
if [ "$1" = "stop" ]
then
echo "Filewall completely stopped!no firewall running!"
exit 0
fi

#setting for loopback interface
$IPT -A INPUT -i lo -j ACCEPT
$IPT -A OUTPUT -o lo -j ACCEPT

# Stealth Scans and TCP State Flags
# All of the bits are cleared
$IPT -A INPUT -p tcp --tcp-flags ALL NONE -j DROP
# SYN and FIN are both set
$IPT -A INPUT -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
# SYN and RST are both set
$IPT -A INPUT -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
# FIN and RST are both set
$IPT -A INPUT -p tcp --tcp-flags FIN,RST FIN,RST -j DROP
# FIN is the only bit set, without the expected accompanying ACK
$IPT -A INPUT -p tcp --tcp-flags ACK,FIN FIN -j DROP
# PSH is the only bit set, without the expected accompanying ACK
$IPT -A INPUT -p tcp --tcp-flags ACK,PSH PSH -j DROP
# URG is the only bit set, without the expected accompanying ACK
$IPT -A INPUT -p tcp --tcp-flags ACK,URG URG -j DROP

# Using Connection State to By-pass Rule Checking
if [ "$CONNECTION_TRACKING" = "1" ]; then
$IPT -A INPUT  -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPT -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPT -A INPUT -m state --state INVALID -j DROP
$IPT -A OUTPUT -m state --state INVALID -j DROP
fi

##################################################################
# Source Address Spoofing and Other Bad Addresses

# Refuse spoofed packets pretending to be from
# the external interface.s IP address

# Refuse packets claiming to be from a Class A private network
$IPT -A INPUT  -i $INTERNET -s $CLASS_A -j DROP

# Refuse packets claiming to be from a Class B private network
$IPT -A INPUT  -i $INTERNET -s $CLASS_B -j DROP

# Refuse packets claiming to be from a Class C private network
$IPT -A INPUT  -i $INTERNET -s $CLASS_C -j DROP

$IPT -A INPUT -i $INTERNET -s 0.0.0.0/8 -j DROP
$IPT -A INPUT -i $INTERNET -s 169.254.0.0/16 -j DROP
$IPT -A INPUT -i $INTERNET -s 192.0.2.0/24 -j DROP
###################################################################
#setting access rules

#也可以对出站的诅求做一些严格的控制
#时钟同步
#$IPT -A OUTPUT -d 192.43.244.18 -j ACCEPT
#允许ping出
#$IPT -A OUTPUT -p icmp -j ACCEPT
#$IPT -A OUTPUT -o $INTERNET -p udp  --dport 53 -j ACCEPT
#$IPT -A OUTPUT -o $INTERNET -p tcp  --dport 80 -j ACCEPT
#$IPT -A INPUT -i $INTERNET -p tcp -m mac --mac-source 00:02:3F:EB:E2:01  --dport 22 -j ACCEPT
$IPT -A INPUT -i $INTERNET -p tcp -s 192.168.9.201 --dport 65535 -j ACCEPT
$IPT -A INPUT -i $INTERNET -p tcp  --dport 443 -j ACCEPT
$IPT -A INPUT -i $INTERNET -p tcp  --dport 80 -j ACCEPT
#限制连往本机的web服务，单个IP的并发连接不超过30个，超过的被拒绝
#$IPT -A INPUT -i $INTERNET -p tcp --dport 80 -m connlimit --connlimit-above 30 -j REJECT
#限制连往本机的web服务，单个IP在60秒内只允许最多新建30个连接，超过的被拒绝
#$IPT -A INPUT -i $INTERNET -p tcp --dport 80 -m recent --name BAD_HTTP_ACCESS --update --seconds 60 --hitcount 30 -j REJECT
#$IPT -A INPUT -i $INTERNET -p tcp --dport 80 -m recent --name BAD_HTTP_ACCESS --set -j ACCEPT
#限制连往本机的web服务，1个C段的IP的并发连接不超过100个，超过的被拒绝
#$IPT -A INPUT -i $INTERNET -p tcp --dport 80 -m iplimit --iplimit-above 100 --iplimit-mask 24 -j REJECT
#$IPT -A INPUT -i $INTERNET -p tcp -s 127.0.0.1 --dport 3306 -j ACCEPT
#$IPT -A INPUT -i $INTERNET -p udp  --dport 123 -j ACCEPT