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675 richard 1 
#!/bin/sh
64 franck 2 
# $Id: alcasar-iptables.sh 770 2011-11-16 20:53:35Z richard $
675 richard 3 
# Script de mise en place des regles du parefeu d'Alcasar (mode normal)
568 richard 4 
# This script write the netfilter rules for ALCASAR
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# Rexy - 3abtux - CPN
6 
#
7 
# Reminders
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# There are three channels for log :
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#	1 (default) for tracability;
10 
#	2 for secure admin (ssh);
11 
#	3 for exterior access attempts.
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# The French Security Agency (ANSSI) rules was applied by 'alcasar.sh' script
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# The bootps/dhcp (67) port is always open on tun0/eth1 by coova
1 root 14 
 
612 richard 15 
conf_file="/usr/local/etc/alcasar.conf"
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private_ip_mask=`grep PRIVATE_IP= $conf_file|cut -d"=" -f2`
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private_ip_mask=${private_ip_mask:=192.168.182.1/24}
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private_network=`/bin/ipcalc -n $private_ip_mask|cut -d"=" -f2`		# LAN IP address (ie.: 192.168.182.0)
19 
private_prefix=`/bin/ipcalc -p $private_ip_mask|cut -d"=" -f2`		# LAN prefix (ie. 24)
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dns1=`grep DNS1= $conf_file|cut -d"=" -f2`				# first public DNS server
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dns1=${dns1:=208.67.220.220}
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dns2=`grep DNS2= $conf_file|cut -d"=" -f2`				# second public DNS server
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dns2=${dns2:=208.67.222.222}
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PROTOCOLS_FILTERING=`grep PROTOCOLS_FILTERING= $conf_file|cut -d"=" -f2`	# Network protocols filter (on/off)
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PROTOCOLS_FILTERING=${PROTOCOLS_FILTERING:=off}
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DNS_FILTERING=`grep DNS_FILTERING= $conf_file|cut -d"=" -f2`		# DNS and URLs filter (on/off)
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DNS_FILTERING=${DNS_FILTERING:=off}
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QOS=`grep QOS= $conf_file|cut -d"=" -f2`					# QOS (on/off)
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QOS=${QOS:=off}
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SSH=`grep SSH= $conf_file|cut -d"=" -f2`					# sshd active (on/off)
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SSH=${SSH:=off}
694 franck 32 
Admin_from_IP=${Admin_from_IP:="0.0.0.0/0.0.0.0"}			# Une @IP fixe peut-être fournie pour restreindre l'accès en ssh depuis l'extérieur (ex: 80.22.21.53/24) ( 0.0.0.0/0.0.0.0  = de n'importe où ! )
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LDAP=`grep LDAP= $conf_file|cut -d"=" -f2`				# ldap external server active (on/off)
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LDAP=${LDAP:=off}
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LDAP_IP=`grep LDAP_IP= $conf_file|cut -d"=" -f2`			# ldap external server IP address
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LDAP_IP=${LDAP_IP:="0.0.0.0/0.0.0.0"}
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PRIVATE_NETWORK_MASK=$private_network/$private_prefix			# Lan IP address + prefix (192.168.182.0/24)
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PRIVATE_IP=`echo $private_ip_mask | cut -d"/" -f1`			# ALCASAR LAN IP address
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DNSSERVERS="$dns1,$dns2"						# first and second DNS IP servers addresses
675 richard 40 
EXTIF="eth0"
1 root 41 
INTIF="eth1"
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TUNIF="tun0"								# listen card for chilli daemon
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IPTABLES="/sbin/iptables"
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498 richard 45 
# Effacement des règles existantes
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# Flush all existing rules
1 root 47 
$IPTABLES -F
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$IPTABLES -t nat -F
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$IPTABLES -t mangle -F
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$IPTABLES -F INPUT
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$IPTABLES -F FORWARD
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$IPTABLES -F OUTPUT
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498 richard 54 
# Suppression des chaines utilisateurs sur les tables filter et nat
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# Flush non default rules on filter and nat tables
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$IPTABLES -X
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$IPTABLES -t nat -X
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59 
# Stratégies par défaut
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# Default policies
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$IPTABLES -P INPUT DROP
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$IPTABLES -P FORWARD DROP
498 richard 63 
$IPTABLES -P OUTPUT DROP
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$IPTABLES -t nat -P PREROUTING ACCEPT
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$IPTABLES -t nat -P POSTROUTING ACCEPT
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$IPTABLES -t nat -P OUTPUT ACCEPT
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498 richard 68 
# Tout passe sur loopback
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# accept all on loopback
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$IPTABLES -A INPUT -i lo -j ACCEPT
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472 richard 72 
#############################
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#       INTIF rules         #
74 
#############################
675 richard 75 
# interdit l'accès à INTIF (n'est utile que lorsque chilli est arrêté).
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# Reject INTIF access (only when chilli is down)
1 root 77 
$IPTABLES -A INPUT -i $INTIF -j ULOG --ulog-prefix "RULE Protect1 -- REJECT "
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$IPTABLES -A INPUT -i $INTIF -j REJECT
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472 richard 80 
#############################
81 
#  Local protection rules   #
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#############################
675 richard 83 
# On stoppe les demande de connexions non conformes (NullScan, XMAS (tous flags à 1), NEW not SYN, etc.)
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# Drop non standard connexions (NULLscans, XMAS, "NEW not SYN", etc.)
472 richard 85 
$IPTABLES -A INPUT -p tcp --tcp-flags FIN,URG,PSH FIN,URG,PSH -j DROP
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$IPTABLES -A INPUT -p tcp --tcp-flags ALL ALL -j DROP
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$IPTABLES -A INPUT -p tcp --tcp-flags ALL NONE -j DROP
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$IPTABLES -A INPUT -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
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$IPTABLES -A INPUT -p tcp -m tcp ! --syn -m state --state NEW -j DROP
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675 richard 91 
# On ne traite pas les broadcasts et multicast
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# Drop broadcast & multicast
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$IPTABLES -A INPUT -m addrtype --dst-type BROADCAST,MULTICAST -j DROP
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95 
# Rejet des tentatives de création de tunnels DNS (même pour les utilisateurs authentifiés)
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# Deny forward DNS (even for authenticated users ...)
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$IPTABLES -A FORWARD -i $TUNIF -p udp --dport domain -j REJECT --reject-with icmp-port-unreachable
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$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport domain -j REJECT --reject-with tcp-reset
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498 richard 100 
# On autorise les retours de connexions légitimes par FORWARD
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# Conntrack on forward
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$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
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520 richard 104 
###############################
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#  If DNS filter is activate  #
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###############################
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# Redirection des flux DNS vers le port 54 (dns+blackhole) sauf pour les IP en exceptions
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if [ $DNS_FILTERING = on ]; then
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	# Compute exception IP
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	nb_exceptions=`wc -l /usr/local/etc/alcasar-filter-exceptions | cut -d" " -f1`
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	if [ $nb_exceptions != "0" ]
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	then
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		while read ip_exception
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		do
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			$IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -s $ip_exception -d $PRIVATE_IP --dport domain -j ACCEPT
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		done < /usr/local/etc/alcasar-filter-exceptions
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	fi
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		$IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -d $PRIVATE_IP --dport domain -j REDIRECT --to-port 54
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fi
476 richard 120 
#####################################
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#  If protocols filter is activate  #
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#####################################
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if [ $PROTOCOLS_FILTERING = on ]; then
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	# Compute exception IP (IP addresses that shouldn't be filtered)
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	nb_exceptions=`wc -l /usr/local/etc/alcasar-filter-exceptions | cut -d" " -f1`
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	if [ $nb_exceptions != "0" ]
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	then
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		while read ip_exception
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		do
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			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j ULOG --ulog-prefix "RULE IP-exception -- ACCEPT "
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			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j ACCEPT
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		done < /usr/local/etc/alcasar-filter-exceptions
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	fi
688 richard 134 
	# Compute uamallowed IP (IP address of equipments connect between ALCASAR and Internet (DMZ, own servers, ...)
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	nb_exceptions=`wc -l /usr/local/etc/alcasar-uamallowed | cut -d" "  -f1`
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	if [ $nb_exceptions != "0" ]
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	then
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		while read ip_allowed_line
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		do
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			ip_allowed=`echo $ip_allowed_line|cut -d"\"" -f2`
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			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j ULOG --ulog-prefix "RULE IP-allowed -- ACCEPT "
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			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j ACCEPT
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		done < /usr/local/etc/alcasar-uamallowed
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	fi
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	# Autorisation des protocoles non commentés
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	# Allow non comment protocols
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	while read svc_line
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	do
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		svc_on=`echo $svc_line|cut -b1`
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		if [ $svc_on != "#" ]
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		then
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			svc_name=`echo $svc_line|cut -d" " -f1`
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			svc_port=`echo $svc_line|cut -d" " -f2`
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			if [ $svc_name = "icmp" ]
155 
			then
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				$IPTABLES -A FORWARD -i $TUNIF -p icmp -j ACCEPT
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			else
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				$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport $svc_port -m state --state NEW -j ULOG --ulog-prefix "RULE F_$svc_name -- ACCEPT "
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				$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport $svc_port -m state --state NEW -j ACCEPT
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			fi
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		fi
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	done < /usr/local/etc/alcasar-services
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	# Rejet explicite (vers le LAN) des autres protocoles
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	# reject the others
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	$IPTABLES -A FORWARD -i $TUNIF -p tcp -j ULOG --ulog-prefix "RULE F_filter -- REJECT "
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	$IPTABLES -A FORWARD -i $TUNIF -p tcp -j REJECT --reject-with tcp-reset
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	$IPTABLES -A FORWARD -i $TUNIF -p udp -j REJECT --reject-with icmp-port-unreachable
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	$IPTABLES -A FORWARD -i $TUNIF -p icmp -j REJECT
1 root 169 
fi
492 franck 170 
 
171 
########################
172 
#  If QOS is activate  #
173 
########################
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if [ $QOS = on ] && [ -e /usr/local/etc/alcasar-iptables-qos.sh ]; then
492 franck 175 
	. /usr/local/etc/alcasar-iptables-qos.sh
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fi
177 
 
498 richard 178 
# Autorisation des connections sortant du LAN
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# Allow forward connections with log
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$IPTABLES -A FORWARD -i $TUNIF -m state --state NEW -j ULOG --ulog-prefix "RULE F_all -- ACCEPT "
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$IPTABLES -A FORWARD -i $TUNIF -m state --state NEW -j ACCEPT
1 root 182 
 
604 richard 183 
#################################################################################################
184 
#  Direct input from local network (icmp, dns, ntp, https, http, ssh and 3990 (user disconnect) #
185 
#################################################################################################
186 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -p icmp --icmp-type 0 -j ACCEPT # ping reply
187 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -p icmp --icmp-type 8 -j ACCEPT # ping request
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$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p udp --dport domain -j ACCEPT # dnsmasq without forward
189 
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p udp --dport 54 -j ACCEPT # dnsmasq with blackhole
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$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p udp --dport ntp -j ACCEPT
191 
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport https -j ACCEPT
192 
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport http -j ACCEPT
193 
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport 3990 -j ACCEPT
604 richard 194 
# SSHD rules if activate
612 richard 195 
if [ $SSH = on ]
604 richard 196 
	then
197 
	$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport ssh -m state --state NEW -j ULOG --ulog-nlgroup 2 --ulog-prefix "RULE ssh-from-LAN -- ACCEPT"
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	$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport ssh -j ACCEPT
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	$IPTABLES -A INPUT -i $EXTIF -p tcp --dport ssh -s $Admin_from_IP -m state --state NEW --syn -j ULOG --ulog-nlgroup 2 --ulog-prefix "RULE ssh-from-WAN -- ACCEPT"
200 
	$IPTABLES -A INPUT -i $EXTIF -p tcp --dport ssh -s $Admin_from_IP -m state --state NEW,ESTABLISHED -j ACCEPT
201 
	$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport ssh -m state --state ESTABLISHED -j ACCEPT
202 
fi
203 
 
204 
# Insertion de règles locales
694 franck 205 
# Here, we add local rules (i.e. VPN from Internet)
604 richard 206 
if [ -f /usr/local/etc/alcasar-iptables-local.sh ]; then
207 
        . /usr/local/etc/alcasar-iptables-local.sh
208 
fi
209 
 
498 richard 210 
# On autorise les retours de connexions légitimes par INPUT
476 richard 211 
# Conntrack on INPUT
1 root 212 
$IPTABLES -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
213 
 
520 richard 214 
# On interdit les connexions directes au port utilisé par DansGuardian (8080)
498 richard 215 
# Les packets concernés ont fait l'objet d'un marquage dans la table mangle
216 
# lors d'une règle de PREROUTING (voir plus bas)
520 richard 217 
# Deny direct connections on DansGuardian port (8080)
476 richard 218 
# The concerned paquets are marked by a pre-routing rule (see further)
770 richard 219 
$IPTABLES -A INPUT -i $TUNIF -p tcp --dport 8080 -m mark --mark 1 -j REJECT --reject-with tcp-reset
520 richard 220 
# Autorisation des connexions à DansGuardian
221 
# Allow connections for DansGuardian
1 root 222 
$IPTABLES -A INPUT -i $TUNIF -p tcp --dport 8080 -m state --state NEW --syn -j ACCEPT
223 
 
498 richard 224 
# Journalisation des requètes HTTP (seulement des paquets SYN)
476 richard 225 
# Log HTTP requests (only syn)
226 
$IPTABLES -A PREROUTING -t nat -i $TUNIF -p tcp ! -d $PRIVATE_IP --dport http -m state --state NEW -j ULOG --ulog-prefix "RULE F_http -- ACCEPT "
498 richard 227 
# On redirige les requêtes HTTP vers DansGuardian (transparent pour les utilisateurs)
476 richard 228 
# Redirect HTTP request in DansGuardian (transparent proxy)
1 root 229 
$IPTABLES -A PREROUTING -t nat -i $TUNIF -p tcp ! -d $PRIVATE_IP --dport http -j REDIRECT --to-port 8080
520 richard 230 
# Journalisation et marquage des paquets qui tentent d'accéder directement à DansGuardian
498 richard 231 
# pour pouvoir les supprimer en INPUT (voir plus haut)
520 richard 232 
# Mark the dansguardian bypass attempts
1 root 233 
$IPTABLES -A PREROUTING -t nat -i $TUNIF -p tcp -d $PRIVATE_IP -m tcp --dport 8080 -j ULOG --ulog-prefix "RULE direct-proxy -- DENY "
234 
$IPTABLES -A PREROUTING -t mangle -i $TUNIF -p tcp -d $PRIVATE_IP -m tcp --dport 8080 -j MARK --set-mark 1
726 franck 235 
# On redirige les requêtes NTP vers le serveur NTP local
236 
# Redirect NTP request in local NTP server
237 
$IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp ! -d $PRIVATE_IP --dport ntp -j REDIRECT --to-port 123
1 root 238 
 
498 richard 239 
# Journalisation et rejet des connexions (autres que celles autorisées) effectuées depuis le LAN
476 richard 240 
# Deny and log on INPUT from the LAN
241 
$IPTABLES -A INPUT -i $TUNIF -m state --state NEW -j ULOG --ulog-prefix "RULE rej-int -- REJECT "
472 richard 242 
$IPTABLES -A INPUT -i $TUNIF -p tcp -j REJECT --reject-with tcp-reset
243 
$IPTABLES -A INPUT -i $TUNIF -p udp -j REJECT --reject-with icmp-port-unreachable
492 franck 244 
 
498 richard 245 
# Journalisation et rejet des connexions initiées depuis le réseau extérieur (test des effets du paramètre --limit en cours)
476 richard 246 
# On EXTIF, the access attempts are log in channel 2 (we should test --limit option to avoid deny of service)
247 
$IPTABLES -A INPUT -i $EXTIF -m state --state NEW -j ULOG --ulog-nlgroup 3 --ulog-qthreshold 10 --ulog-prefix "RULE rej-ext -- DROP"
1 root 248 
 
498 richard 249 
#############################
250 
# filtering outside OUTPUT. #
251 
#############################
252 
# On laisse tout sortir sur toutes les cartes sauf celle qui est connectée sur l'extérieur
253 
# Everything is allowed but traffic through outside network interface
254 
$IPTABLES -A OUTPUT ! -o $EXTIF -j ACCEPT
520 richard 255 
 
503 richard 256 
# On autorise les requêtes DNS vers les serveurs DNS identifiés
498 richard 257 
# Allow DNS requests to identified DNS servers
258 
$IPTABLES -A OUTPUT -o $EXTIF -d $DNSSERVERS -p udp --dport domain -m state --state NEW -j ACCEPT
615 richard 259 
# On autorise les requêtes HTTP sortantes
498 richard 260 
# HTTP requests are allowed
261 
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --dport http -j ACCEPT
615 richard 262 
# On autorise les requêtes NTP
498 richard 263 
# NTP requests are allowed
264 
$IPTABLES -A OUTPUT -o $EXTIF -p udp --dport ntp -j ACCEPT
503 richard 265 
# On autorise les requêtes ICMP (ping)
266 
# ICMP (ping) requests are allowed
267 
$IPTABLES -A OUTPUT -o $EXTIF -p icmp --icmp-type 8 -j ACCEPT
615 richard 268 
# On autorise les requêtes LDAP si un serveur externe est configué
269 
# LDAP requests are allowed if an external server is declared
270 
if [ $LDAP = on ]
271 
	then
694 franck 272 
	$IPTABLES -A OUTPUT -p tcp -d $LDAP_IP -m multiport --dports ldap,ldaps -m state --state NEW,ESTABLISHED -j ACCEPT
273 
	$IPTABLES -A OUTPUT -p udp -d $LDAP_IP -m multiport --dports ldap,ldaps -m state --state NEW,ESTABLISHED -j ACCEPT
274 
#	$IPTABLES -A INPUT  -p tcp -s $LDAP_IP -m multiports --sports ldap,ldaps -m state --state ESTABLISHED -j ACCEPT
275 
#	$IPTABLES -A INPUT  -p udp -s $LDAP_IP -m multiports --sports ldap,ldaps -m state --state ESTABLISHED -j ACCEPT
615 richard 276 
fi
498 richard 277 
# Traduction dynamique d'adresse en sortie
476 richard 278 
# Dynamic NAT on EXTIF
1 root 279 
$IPTABLES -A POSTROUTING -t nat -o $EXTIF -j MASQUERADE
280 
 
476 richard 281 
# Save all rules
1 root 282 
/etc/init.d/iptables save
283 
 
476 richard 284 
# End of script
1 root 285