[Comm] Re: Bridging firewall

[Guest007 <trash4@yandex.ru>]

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В сообщении от Суббота 18 Сентябрь 2004 20:57 Denis Smirnov написал(a):
> On Fri, Sep 17, 2004 at 01:57:36PM +0400, Guest007 wrote:
>
>  G> А в моей реальной ситуации всё было просто: мы ходим в Большой Мир
> через G> breezaccess и оконечное устройство, хотя и имеет ethernet, но
> работает только G> с одним МАК-адресом. Вот когда кроме роутера
> потребовалось дать реальный IP G> еще одному устройству (именно для .323),
> тогда я и выкинул ея наружу. G> Так что не ошибусь, если скажу, что, таки
> да, .323 через НАТ средствами G> iptables ходит без вопросов.
>
> Показывай настройки, версии и т.д. В общем делись "как это у тебя
> получилось", ибо мне на днях как раз придётся страдать этим же
> удовольствием.
Я там в конференцию ответил, но у меня есть еще пара вопросов, и, если ты 
сможешь, помогои, пожалуйста. 

Свой скрипт я приложил. Глянь, пожалуйста, что я там недоработал? 

1) Из локальной сети .323 устройство не пингуется. Почему? (вообще ничего не 
пингуется, кроме 192.168.6.100, значит ICMP пакеты не проходят цепочки, а 
где-то дропаются) Что я забыл прописать? 
2) по 80 порту могу зайти, пользуя локальный адрес (192.168.16.4), а НетМитинг 
сделать не могу. Значит из одного сегмента в другой не ходят УДП пакеты. Что 
еще подкрутить?

Заранее благодарен.

-- 
WBR Guest007
JID: guest007@jabber.ru

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#!/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="194.22x.xxx.1" #will be i-face (real ip)
VS_IP="194.22x.xxx.2" #will be viewstation (alias)
INET_IFACE="eth0"
INET_BROADCAST="194.22x.xxx.255"
#
# 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="192.168.6.100"
LAN_IFACE="eth1"

#
# 1.3 DMZ Configuration.
#

DMZ_VS_IP="192.168.16.4"
DMZ_IP="192.168.16.1"
DMZ_IFACE="eth2"

#
# 1.4 Localhost Configuration.
#

LO_IFACE="lo"
LO_IP="127.0.0.1"

#
# 1.5 IPTables Configuration.
#

IPTABLES="/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
$IPTABLES -A INPUT -p TCP -s 192.168.6.77 --destination-port 22 \
-m state --state NEW -j ACCEPT
#
# 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 $DMZ_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

#$IPTABLES -A INPUT -p TCP -i $LAN_IFACE -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_VS_IP \
--dport 80 -j allowed

#
# ViewStation
#
$IPTABLES -A FORWARD -p TCP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_VS_IP \
--dport 1720 -j allowed
$IPTABLES -A FORWARD -p TCP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_VS_IP \
--dport 1503 -j allowed
# б ЛН╦Л ЯКСВЮЕ ЩРНР ОНПР МЕ ЪБКЪЕРЯЪ МЕНАУНДХЛНЯРЭЧ.... 
# Guest007


$IPTABLES -A FORWARD -p TCP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_VS_IP \
--dport 3230:3235 -j allowed

$IPTABLES -A FORWARD -p UDP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_VS_IP \
--dport 3230:3247 -j ACCEPT


$IPTABLES -A FORWARD -p ICMP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_VS_IP \
-j icmp_packets

#$IPTABLES -A FORWARD -p ICMP -i $LAN_IFACE -o $DMZ_IFACE -d $DMZ_VS_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 $VS_IP --dport 80 \
-j DNAT --to-destination $DMZ_VS_IP

$IPTABLES -t nat -A PREROUTING -p TCP -i $INET_IFACE -d $VS_IP --dport 1503 \
-j DNAT --to-destination $DMZ_VS_IP
$IPTABLES -t nat -A PREROUTING -p TCP -i $INET_IFACE -d $VS_IP --dport 1720 \
-j DNAT --to-destination $DMZ_VS_IP

$IPTABLES -t nat -A PREROUTING -p TCP -i $INET_IFACE -d $VS_IP --dport 3230:3235 \
-j DNAT --to-destination $DMZ_VS_IP

$IPTABLES -t nat -A PREROUTING -p UDP -i $INET_IFACE -d $VS_IP --dport 3230:3247 \
-j DNAT --to-destination $DMZ_VS_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
#