I.2. Пример rc.DMZ.firewall
#!/bin/sh # # rc.DMZ.firewall - DMZ IP Firewall script
for Linux 2.4.x and iptables # # Copyright (C) 2001 Oskar Andreasson <
bluefluxATkoffeinDOTnet> # # This program is free software; you can
redistribute it and/or modify # it under the terms of the GNU General
Public License as published by # the Free Software Foundation; version
2 of the License. # # This program is distributed in the hope
that it will be useful, # but WITHOUT ANY WARRANTY; without even the
implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU
General Public License # along with this program or from the site
that you downloaded it # from; if not, write to the Free Software
Foundation, Inc., 59 Temple # Place, Suite 330, Boston, MA 02111-1307 USA #
####################################### # # 1. Configuration options. #
# # 1.1 Internet Configuration. #
INET_IP="194.236.50.152" HTTP_IP="194.236.50.153" DNS_IP="194.236.50.154" INET_IFACE="eth0"
# # 1.1.1 DHCP #
# # 1.1.2 PPPoE #
# # 1.2 Local Area Network configuration. # # your LAN's IP range and localhost IP.
/24 means to only use the first 24 # bits of the 32 bit IP address. the same
as netmask 255.255.255.0 #
LAN_IP="192.168.0.1" LAN_IFACE="eth1"
# # 1.3 DMZ Configuration. #
DMZ_HTTP_IP="192.168.1.2" DMZ_DNS_IP="192.168.1.3" DMZ_IP="192.168.1.1" DMZ_IFACE="eth2"
# # 1.4 Localhost Configuration. #
LO_IFACE="lo" LO_IP="127.0.0.1"
# # 1.5 IPTables Configuration. #
IPTABLES="/usr/sbin/iptables"
# # 1.6 Other Configuration. #
######################################## # # 2. Module loading. #
# # Needed to initially load modules # /sbin/depmod -a
# # 2.1 Required modules #
/sbin/modprobe ip_tables /sbin/modprobe ip_conntrack /sbin/modprobe iptable_filter /sbin/modprobe iptable_mangle /sbin/modprobe iptable_nat /sbin/modprobe ipt_LOG /sbin/modprobe ipt_limit /sbin/modprobe ipt_state
# # 2.2 Non-Required modules #
#/sbin/modprobe ipt_owner #/sbin/modprobe ipt_REJECT #/sbin/modprobe ipt_MASQUERADE #/sbin/modprobe ip_conntrack_ftp #/sbin/modprobe ip_conntrack_irc #/sbin/modprobe ip_nat_ftp #/sbin/modprobe ip_nat_irc
######################################### # # 3. /proc set up. #
# # 3.1 Required proc configuration #
echo "1" > /proc/sys/net/ipv4/ip_forward
# # 3.2 Non-Required proc configuration #
#echo "1" > /proc/sys/net/ipv4/conf/all/rp_filter #echo "1" > /proc/sys/net/ipv4/conf/all/proxy_arp #echo "1" > /proc/sys/net/ipv4/ip_dynaddr
################################################# # # 4. rules set up. #
###### # 4.1 Filter table #
# # 4.1.1 Set policies #
$IPTABLES -P INPUT DROP $IPTABLES -P OUTPUT DROP $IPTABLES -P FORWARD DROP
# # 4.1.2 Create userspecified chains #
# # Create chain for bad tcp packets #
$IPTABLES -N bad_tcp_packets
# # Create separate chains for ICMP, TCP
and UDP to traverse #
$IPTABLES -N allowed $IPTABLES -N icmp_packets
# # 4.1.3 Create content in userspecified chains #
# # bad_tcp_packets chain #
$IPTABLES -A bad_tcp_packets -p tcp
--tcp-flags SYN,ACK SYN,ACK \ -m state --state NEW -j REJECT
--reject-with tcp-reset $IPTABLES -A bad_tcp_packets -p tcp !
--syn -m state --state NEW -j LOG \ --log-prefix "New not syn:" $IPTABLES -A bad_tcp_packets -p tcp !
--syn -m state --state NEW -j DROP
# # allowed chain #
$IPTABLES -A allowed -p TCP
--syn -j ACCEPT $IPTABLES -A allowed -p TCP -m state
--state ESTABLISHED,RELATED -j ACCEPT $IPTABLES -A allowed -p TCP -j DROP
# # ICMP rules #
# Changed rules totally $IPTABLES -A icmp_packets -p ICMP -s 0/0
--icmp-type 8 -j ACCEPT $IPTABLES -A icmp_packets -p ICMP -s 0/0
--icmp-type 11 -j ACCEPT
# # 4.1.4 INPUT chain #
# # Bad TCP packets we don't want #
$IPTABLES -A INPUT -p tcp
-j bad_tcp_packets
# # Packets from the Internet to this box #
$IPTABLES -A INPUT -p ICMP
-i $INET_IFACE -j icmp_packets
# # Packets from LAN, DMZ or LOCALHOST #
# # From DMZ Interface to DMZ firewall IP #
$IPTABLES -A INPUT -p ALL -i $DMZ_IFACE
-d $DMZ_IP -j ACCEPT
# # From LAN Interface to LAN firewall IP #
$IPTABLES -A INPUT -p ALL -i $LAN_IFACE
-d $LAN_IP -j ACCEPT
# # From Localhost interface to Localhost IP's #
$IPTABLES -A INPUT -p ALL -i $LO_IFACE
-s $LO_IP -j ACCEPT $IPTABLES -A INPUT -p ALL -i $LO_IFACE
-s $LAN_IP -j ACCEPT $IPTABLES -A INPUT -p ALL -i $LO_IFACE
-s $INET_IP -j ACCEPT
# # Special rule for DHCP requests from LAN,
which are not caught properly # otherwise. #
$IPTABLES -A INPUT -p UDP -i $LAN_IFACE
--dport 67 --sport 68 -j ACCEPT
# # All established and related packets incoming
from the internet to the # firewall #
$IPTABLES -A INPUT -p ALL -d $INET_IP -m state
--state ESTABLISHED,RELATED \ -j ACCEPT
# # In Microsoft Networks you will be swamped
by broadcasts. These lines # will prevent them from showing up in the logs. #
#$IPTABLES -A INPUT -p UDP -i $INET_IFACE
-d $INET_BROADCAST \ #--destination-port 135:139 -j DROP
# # If we get DHCP requests from the Outside
of our network, our logs will # be swamped as well. This rule will block
them from getting logged. #
#$IPTABLES -A INPUT -p UDP -i $INET_IFACE
-d 255.255.255.255 \ #--destination-port 67:68 -j DROP
# # If you have a Microsoft Network on the
outside of your firewall, you may # also get flooded by Multicasts. We drop
them so we do not get flooded by # logs #
#$IPTABLES -A INPUT -i $INET_IFACE
-d 224.0.0.0/8 -j DROP
# # Log weird packets that don't match the above. #
$IPTABLES -A INPUT -m limit --limit 3/minute
--limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix
"IPT INPUT packet died: "
# # 4.1.5 FORWARD chain #
# # Bad TCP packets we don't want #
$IPTABLES -A FORWARD -p tcp -j bad_tcp_packets
# # DMZ section # # General rules #
$IPTABLES -A FORWARD -i $DMZ_IFACE
-o $INET_IFACE -j ACCEPT $IPTABLES -A FORWARD -i $INET_IFACE
-o $DMZ_IFACE -m state \ --state ESTABLISHED,RELATED -j ACCEPT $IPTABLES -A FORWARD -i $LAN_IFACE
-o $DMZ_IFACE -j ACCEPT $IPTABLES -A FORWARD -i $DMZ_IFACE
-o $LAN_IFACE -m state \ --state ESTABLISHED,RELATED -j ACCEPT
# # HTTP server #
$IPTABLES -A FORWARD -p TCP -i $INET_IFACE
-o $DMZ_IFACE -d $DMZ_HTTP_IP \ --dport 80 -j allowed $IPTABLES -A FORWARD -p ICMP -i $INET_IFACE
-o $DMZ_IFACE -d $DMZ_HTTP_IP \ -j icmp_packets
# # DNS server #
$IPTABLES -A FORWARD -p TCP -i $INET_IFACE
-o $DMZ_IFACE -d $DMZ_DNS_IP \ --dport 53 -j allowed $IPTABLES -A FORWARD -p UDP -i $INET_IFACE
-o $DMZ_IFACE -d $DMZ_DNS_IP \ --dport 53 -j ACCEPT $IPTABLES -A FORWARD -p ICMP -i $INET_IFACE
-o $DMZ_IFACE -d $DMZ_DNS_IP \ -j icmp_packets
# # LAN section #
$IPTABLES -A FORWARD -i $LAN_IFACE -j ACCEPT $IPTABLES -A FORWARD -m state --state
ESTABLISHED,RELATED -j ACCEPT
# # Log weird packets that don't match the above. #
$IPTABLES -A FORWARD -m limit --limit 3/minute
--limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix "IPT FORWARD packet died: "
# # 4.1.6 OUTPUT chain #
# # Bad TCP packets we don't want. #
$IPTABLES -A OUTPUT -p tcp -j bad_tcp_packets
# # Special OUTPUT rules to
decide which IP's to allow. #
$IPTABLES -A OUTPUT -p ALL -s $LO_IP -j ACCEPT $IPTABLES -A OUTPUT -p ALL -s $LAN_IP -j ACCEPT $IPTABLES -A OUTPUT -p ALL -s $INET_IP -j ACCEPT
# # Log weird packets that don't
match the above. #
$IPTABLES -A OUTPUT -m limit --limit 3/minute
--limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix
"IPT OUTPUT packet died: "
###### # 4.2 nat table #
# # 4.2.1 Set policies #
# # 4.2. 2 Create user specified chains #
# # 4.2.3 Create content in user specified chains #
# # 4.2.4 PREROUTING chain #
$IPTABLES -t nat -A PREROUTING -p TCP -i
$INET_IFACE -d $HTTP_IP --dport 80 \ -j DNAT --to-destination $DMZ_HTTP_IP $IPTABLES -t nat -A PREROUTING -p TCP -i
$INET_IFACE -d $DNS_IP --dport 53 \ -j DNAT --to-destination $DMZ_DNS_IP $IPTABLES -t nat -A PREROUTING -p UDP -i
$INET_IFACE -d $DNS_IP --dport 53 \ -j DNAT --to-destination $DMZ_DNS_IP
# # 4.2.5 POSTROUTING chain #
# # Enable simple IP Forwarding and Network
Address Translation #
$IPTABLES -t nat -A POSTROUTING -o $INET_IFACE
-j SNAT --to-source $INET_IP
# # 4.2.6 OUTPUT chain #
###### # 4.3 mangle table #
# # 4.3.1 Set policies #
# # 4.3.2 Create user specified chains #
# # 4.3.3 Create content in user specified chains #
# # 4.3.4 PREROUTING chain #
# # 4.3.5 INPUT chain #
# # 4.3.6 FORWARD chain #
# # 4.3.7 OUTPUT chain #
# # 4.3.8 POSTROUTING chain #
