分享一个Linux防火墙脚本

一个Linux防火墙脚本,不知对大家有帮助吗?

#Set variable
IPT=/sbin/iptables
MAILSER=192.168.1.1
#Load module
modprobe ip_conntrack
modprobe ip_conntrack_ftp
#clear and flush rule
$IPT -F
$IPT -X
#Set default policy
$IPT -P INPUT DROP
$IPT -P FORWARD DROP
$IPT -P OUTPUT DROP
#Set input chain
$IPT -A INPUT -m state --state  ESTABLISHED,RELATED -j ACCEPT
$IPT -A INPUT -p tcp --dport 22 -j LOG --log-level 5 --log-prefix "IPTABLES:"
$IPT -A INPUT -p tcp -d $MAILSER --dport 22 -j ACCEPT
$IPT -A INPUT -p tcp -d $MAILSER --dport 80 -j ACCEPT
$IPT -A INPUT -p udp --dport 53 -j ACCEPT
$IPT -A INPUT -i lo -j ACCEPT
$IPT -A INPUT -p tcp -d $MAILSER --dport 25 -j ACCEPT
$IPT -A INPUT -p tcp -d $MAILSER --dport 110 -j ACCEPT
$IPT -A INPUT -p tcp -d $MAILSER --dport 143 -j ACCEPT
#Set output chain
$IPT -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPT -A OUTPUT -p udp --sport 53 -j ACCEPT
$IPT -A OUTPUT -o lo  -j ACCEPT
$IPT -A OUTPUT -p tcp --sport 25 -j ACCEPT
$IPT -A OUTPUT -p tcp --sport 110 -j ACCEPT
$IPT -A OUTPUT -p tcp --sport 143 -j ACCEPT
#Set forward chain
$IPT -A POSTROUTING -t nat -s 192.168.0.0/24 -o eth0 -j MASQUERADE
$IPT -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPT -A FORWARD -s 192.168.0.0/24 -j ACCEPT
#4444/445/69/135/139
iptables -A FORWARD -p tcp --dport 4444 -j DROP
iptables -A FORWARD -p udp --dport 4444 -j DROP
#
iptables -A FORWARD -p tcp --dport 445 -j DROP
iptables -A FORWARD -p udp --dport 445 -j DROP
#
iptables -A FORWARD -p tcp --dport 69 -j DROP
iptables -A FORWARD -p udp --dport 69 -j DROP
#
iptables -A FORWARD -p tcp --dport 135 -j DROP
iptables -A FORWARD -p udp --dport 135 -j DROP
#
iptables -A FORWARD -p tcp --dport 139 -j DROP
iptables -A FORWARD -p udp --dport 139 -j DROP
#
echo 1 > /proc/sys/net/ipv4/ip_forward
#echo finish messages
echo "finish !!!"