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675 richard 1 
#!/bin/sh
64 franck 2 
# $Id: alcasar-iptables.sh 783 2011-12-17 14:24:08Z 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
675 richard 5 
# 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 'this script
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# The bootps/dhcp (67) port is always open on tun0/eth1 by coova
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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_IP=`echo $private_ip_mask | cut -d"/" -f1`			# ALCASAR LAN IP address
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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 $private_ip_mask|cut -d"=" -f2`		# LAN prefix (ie. 24)
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PRIVATE_NETWORK_MASK=$private_network/$private_prefix			# Lan IP address + prefix (192.168.182.0/24)
21 
public_ip_mask=`grep PUBLIC_IP= $conf_file|cut -d"=" -f2`		# ALCASAR WAN IP address
22 
PUBLIC_IP=`echo $public_ip_mask | cut -d"/" -f1`
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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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DNSSERVERS="$dns1,$dns2"						# first and second DNS IP servers addresses
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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}
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Admin_from_IP=${Admin_from_IP:="0.0.0.0/0.0.0.0"}			# WAN IP address to reduce ssh access (all ip allowed on LAN side)
37 
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= $conf_file|cut -d"=" -f2`			# WAN IP address to reduce LDAP WAN access (all ip allowed on LAN side)
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LDAP_IP=${LDAP_IP:="0.0.0.0/0.0.0.0"}
675 richard 41 
EXTIF="eth0"
1 root 42 
INTIF="eth1"
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TUNIF="tun0"								# listen device for chilli daemon
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IPTABLES="/sbin/iptables"
1 root 45 
 
498 richard 46 
# Effacement des règles existantes
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# Flush all existing rules
1 root 48 
$IPTABLES -F
49 
$IPTABLES -t nat -F
50 
$IPTABLES -t mangle -F
51 
$IPTABLES -F INPUT
52 
$IPTABLES -F FORWARD
53 
$IPTABLES -F OUTPUT
54 
 
498 richard 55 
# Suppression des chaines utilisateurs sur les tables filter et nat
56 
# Flush non default rules on filter and nat tables
57 
$IPTABLES -X
58 
$IPTABLES -t nat -X
59 
 
60 
# Stratégies par défaut
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# Default policies
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$IPTABLES -P INPUT DROP
63 
$IPTABLES -P FORWARD DROP
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$IPTABLES -P OUTPUT DROP
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$IPTABLES -t nat -P PREROUTING ACCEPT
66 
$IPTABLES -t nat -P POSTROUTING ACCEPT
67 
$IPTABLES -t nat -P OUTPUT ACCEPT
68 
 
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#############################
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#       PREROUTING          #
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#############################
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# Marquage (et journalisation) des paquets qui tentent d'accéder directement à DansGuardian pour pouvoir les rejeter en INPUT
73 
# mark (and log) the dansguardian bypass attempts in order to DROP them in INPUT rules
74 
# $IPTABLES -A PREROUTING -t nat -i $TUNIF -p tcp -d $PRIVATE_IP -m tcp --dport 8080 -j ULOG --ulog-prefix "RULE direct-proxy -- DENY "
75 
$IPTABLES -A PREROUTING -t mangle -i $TUNIF -d $PRIVATE_IP -p tcp -m tcp --dport 8080 -j MARK --set-mark 1
1 root 76 
 
783 richard 77 
# Marquage (et journalisation) des paquets qui tentent d'accéder directement au port udp 54 pour pouvoir les rejeter en INPUT
78 
# Mark (and log) the udp 54 direct attempts to REJECT them in INPUT rules
79 
# Remarque : Ce port n'est ouvert que lorsque le filtrage est activé
80 
# Remark : this port is only open when filtering is on
81 
# $IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -d $PRIVATE_IP -m udp --dport 54 -j ULOG --ulog-prefix "RULE DNS-proxy -- DENY "
82 
$IPTABLES -A PREROUTING -t mangle -i $TUNIF -d $PRIVATE_IP -p tcp --dport 54 -j MARK --set-mark 2
83 
 
84 
# Si le filtrage est activé, redirection des flux DNS vers le port 54 (dns+blackhole) sauf pour les IP en exceptions
85 
# If DNS filter is on, redirect DNS request to udp 54 (dns+blackhole) except for exception IP addresses
86 
if [ $DNS_FILTERING = on ]; then
87 
	# Compute exception IP
88 
	nb_exceptions=`wc -l /usr/local/etc/alcasar-filter-exceptions | cut -d" " -f1`
89 
	if [ $nb_exceptions != "0" ]
90 
	then
91 
		while read ip_exception
92 
		do
93 
			$IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -s $ip_exception -d $PRIVATE_IP --dport domain -j ACCEPT
94 
		done < /usr/local/etc/alcasar-filter-exceptions
95 
	fi
96 
		$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport domain -j REDIRECT --to-port 54
97 
fi
98 
 
99 
# Journalisation des requètes HTTP vers Internet (seulement les paquets SYN) - Les autres protocoles sont journalisés en FORWARD
100 
# Log HTTP requests to Internet (only syn packets) - Other protocols are log in FORWARD
101 
$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK ! -d $PRIVATE_IP -p tcp --dport http -m state --state NEW -j ULOG --ulog-prefix "RULE F_http -- ACCEPT "
102 
# Redirection des requêtes HTTP vers DansGuardian (proxy transparent)
103 
# Redirect HTTP requests in DansGuardian (transparent proxy)
104 
$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK ! -d $PRIVATE_IP -p tcp --dport http -j REDIRECT --to-port 8080
105 
 
106 
# Redirection des requêtes NTP vers le serveur NTP local
107 
# Redirect NTP request in local NTP server
108 
$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK ! -d $PRIVATE_IP -p udp --dport ntp -j REDIRECT --to-port 123
109 
 
472 richard 110 
#############################
783 richard 111 
#         INPUT             #
472 richard 112 
#############################
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# Tout passe sur loopback
114 
# accept all on loopback
115 
$IPTABLES -A INPUT -i lo -j ACCEPT
116 
 
117 
# Rejet des demandes de connexions non conformes (FIN-URG-PUSH, XMAS, NullScan, SYN-RST et NEW not SYN)
118 
# Drop non standard connexions (FIN-URG-PUSH, XMAS, NullScan, SYN-RST et NEW not SYN)
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$IPTABLES -A INPUT -p tcp --tcp-flags FIN,URG,PSH FIN,URG,PSH -j DROP
120 
$IPTABLES -A INPUT -p tcp --tcp-flags ALL ALL -j DROP
121 
$IPTABLES -A INPUT -p tcp --tcp-flags ALL NONE -j DROP
122 
$IPTABLES -A INPUT -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
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$IPTABLES -A INPUT -p tcp -m tcp ! --syn -m state --state NEW -j DROP
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783 richard 125 
# On rejète les trame en broadcast et en multicast sur EXTIF (pour ne pas les journaliser)
126 
# Drop broadcast & multicast on EXTIF to not be logged
127 
$IPTABLES -A INPUT -i $EXTIF -m addrtype --dst-type BROADCAST,MULTICAST -j DROP
498 richard 128 
 
783 richard 129 
# On autorise les retours de connexions légitimes par INPUT
130 
# Conntrack on INPUT
131 
$IPTABLES -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
373 richard 132 
 
783 richard 133 
# On interdit les connexions directes au port utilisé par DansGuardian (8080). Les packets concernés ont été marqués dans la table mangle (PREROUTING)
134 
# Deny direct connections on DansGuardian port (8080). The concerned paquets are marked in mangle table (PREROUTING)
135 
$IPTABLES -A INPUT -i $TUNIF -p tcp --dport 8080 -m mark --mark 1 -j REJECT --reject-with tcp-reset
136 
# Autorisation des connexions légitimes à DansGuardian
137 
# Allow connections for DansGuardian
138 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -p tcp --dport 8080 -m state --state NEW --syn -j ACCEPT
373 richard 139 
 
783 richard 140 
# On interdit les connexions directes au port UDP 54. Les packets concernés ont été marqués dans la table mangle (PREROUTING)
141 
# Deny direct connections on UDP 54. The concerned paquets are marked in mangle table (PREROUTING)
142 
$IPTABLES -A INPUT -i $TUNIF -p udp --dport 54 -m mark --mark 2 -j REJECT --reject-with icmp-port-unreachable
143 
# autorisation des connexion légitime à DNSMASQ (avec blackhole)
144 
# Allow connections for DNSMASQ (with blackhole)
145 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport 54 -j ACCEPT
146 
 
147 
# Accès direct aux services internes
148 
# Internal services access
149 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport domain -j ACCEPT # DNS non filtré # DNS without blackhole
150 
#$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -p icmp --icmp-type 8 -j ACCEPT	# Requête ping # ping request
151 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p icmp --icmp-type 0 -j ACCEPT	# Réponse ping # ping reply
152 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport https -j ACCEPT		# Pages d'authentification et MCC # authentication pages and MCC
153 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport http -j ACCEPT		# Page d'avertissement filtrage # Filtering warning pages
154 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport 3990 -j ACCEPT		# Requêtes de deconnexion usagers # Users logout requests
155 
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport ntp -j ACCEPT		# Serveur local de temps # local time server
156 
 
157 
# SSHD rules if activate
158 
if [ $SSH = on ]
520 richard 159 
	then
783 richard 160 
	$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport ssh -m state --state NEW -j ULOG --ulog-nlgroup 2 --ulog-prefix "RULE ssh-from-LAN -- ACCEPT"
161 
	$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport ssh -j ACCEPT
162 
	$IPTABLES -A INPUT -i $EXTIF -s $Admin_from_IP -d $PUBLIC_IP -p tcp --dport ssh -m state --state NEW --syn -j ULOG --ulog-nlgroup 2 --ulog-prefix "RULE ssh-from-WAN -- ACCEPT"
163 
	$IPTABLES -A INPUT -i $EXTIF -s $Admin_from_IP -d $PUBLIC_IP -p tcp --dport ssh -m state --state NEW,ESTABLISHED -j ACCEPT
520 richard 164 
fi
783 richard 165 
 
166 
# Insertion de règles locales
167 
# Here, we add local rules (i.e. VPN from Internet)
168 
if [ -f /usr/local/etc/alcasar-iptables-local.sh ]; then
169 
        . /usr/local/etc/alcasar-iptables-local.sh
170 
fi
171 
 
172 
# Journalisation et rejet des connexions (autres que celles autorisées) effectuées depuis le LAN
173 
# Deny and log on INPUT from the LAN
174 
$IPTABLES -A INPUT -i $TUNIF -m state --state NEW -j ULOG --ulog-prefix "RULE rej-int -- REJECT "
175 
$IPTABLES -A INPUT -i $TUNIF -p tcp -j REJECT --reject-with tcp-reset
176 
$IPTABLES -A INPUT -i $TUNIF -p udp -j REJECT --reject-with icmp-port-unreachable
177 
 
178 
# interdiction d'accès à INTIF (n'est utile que lorsque chilli est arrêté).
179 
# Reject INTIF access (only when chilli is down)
180 
$IPTABLES -A INPUT -i $INTIF -j ULOG --ulog-prefix "RULE Protect1 -- REJECT "
181 
$IPTABLES -A INPUT -i $INTIF -j REJECT
182 
 
183 
# Journalisation et rejet des connexions initiées depuis le réseau extérieur (test des effets du paramètre --limit en cours)
184 
# On EXTIF, the access attempts are log in channel 2 (we should test --limit option to avoid deny of service)
185 
$IPTABLES -A INPUT -i $EXTIF -m state --state NEW -j ULOG --ulog-nlgroup 3 --ulog-qthreshold 10 --ulog-prefix "RULE rej-ext -- DROP"
186 
 
187 
#############################
188 
#        FORWARD            #
189 
#############################
190 
# Autorisation des retours de connexions légitimes
191 
# Allow conntrack
192 
$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
193 
 
194 
# Rejet des requêtes DNS vers Internet
195 
# Deny forward DNS
196 
$IPTABLES -A FORWARD -i $TUNIF -p udp --dport domain -j REJECT --reject-with icmp-port-unreachable
197 
$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport domain -j REJECT --reject-with tcp-reset
198 
 
199 
#  If protocols filter is activate
612 richard 200 
if [ $PROTOCOLS_FILTERING = on ]; then
688 richard 201 
	# Compute exception IP (IP addresses that shouldn't be filtered)
202 
	nb_exceptions=`wc -l /usr/local/etc/alcasar-filter-exceptions | cut -d" " -f1`
373 richard 203 
	if [ $nb_exceptions != "0" ]
204 
	then
205 
		while read ip_exception
206 
		do
207 
			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j ULOG --ulog-prefix "RULE IP-exception -- ACCEPT "
208 
			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j ACCEPT
209 
		done < /usr/local/etc/alcasar-filter-exceptions
210 
	fi
688 richard 211 
	# Compute uamallowed IP (IP address of equipments connect between ALCASAR and Internet (DMZ, own servers, ...)
212 
	nb_exceptions=`wc -l /usr/local/etc/alcasar-uamallowed | cut -d" "  -f1`
213 
	if [ $nb_exceptions != "0" ]
214 
	then
215 
		while read ip_allowed_line
216 
		do
217 
			ip_allowed=`echo $ip_allowed_line|cut -d"\"" -f2`
218 
			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j ULOG --ulog-prefix "RULE IP-allowed -- ACCEPT "
219 
			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j ACCEPT
220 
		done < /usr/local/etc/alcasar-uamallowed
221 
	fi
520 richard 222 
	# Autorisation des protocoles non commentés
476 richard 223 
	# Allow non comment protocols
373 richard 224 
	while read svc_line
225 
	do
226 
		svc_on=`echo $svc_line|cut -b1`
227 
		if [ $svc_on != "#" ]
228 
		then
229 
			svc_name=`echo $svc_line|cut -d" " -f1`
230 
			svc_port=`echo $svc_line|cut -d" " -f2`
231 
			if [ $svc_name = "icmp" ]
232 
			then
233 
				$IPTABLES -A FORWARD -i $TUNIF -p icmp -j ACCEPT
234 
			else
783 richard 235 
				$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport $svc_port -m state --state NEW -j ULOG --ulog-prefix "RULE F_TCP-$svc_name -- ACCEPT "
373 richard 236 
				$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport $svc_port -m state --state NEW -j ACCEPT
783 richard 237 
				$IPTABLES -A FORWARD -i $TUNIF -p udp --dport $svc_port -m state --state NEW -j ULOG --ulog-prefix "RULE F_UDP-$svc_name -- ACCEPT "
238 
				$IPTABLES -A FORWARD -i $TUNIF -p udp --dport $svc_port -m state --state NEW -j ACCEPT
373 richard 239 
			fi
240 
		fi
241 
	done < /usr/local/etc/alcasar-services
783 richard 242 
	# Rejet explicite des autres protocoles
243 
	# reject the others protocols
244 
	$IPTABLES -A FORWARD -i $TUNIF -j ULOG --ulog-prefix "RULE F_filter -- REJECT "
373 richard 245 
	$IPTABLES -A FORWARD -i $TUNIF -p tcp -j REJECT --reject-with tcp-reset
246 
	$IPTABLES -A FORWARD -i $TUNIF -p udp -j REJECT --reject-with icmp-port-unreachable
247 
	$IPTABLES -A FORWARD -i $TUNIF -p icmp -j REJECT
1 root 248 
fi
492 franck 249 
 
250 
########################
251 
#  If QOS is activate  #
252 
########################
612 richard 253 
if [ $QOS = on ] && [ -e /usr/local/etc/alcasar-iptables-qos.sh ]; then
492 franck 254 
	. /usr/local/etc/alcasar-iptables-qos.sh
255 
fi
256 
 
498 richard 257 
# Autorisation des connections sortant du LAN
476 richard 258 
# Allow forward connections with log
259 
$IPTABLES -A FORWARD -i $TUNIF -m state --state NEW -j ULOG --ulog-prefix "RULE F_all -- ACCEPT "
411 richard 260 
$IPTABLES -A FORWARD -i $TUNIF -m state --state NEW -j ACCEPT
1 root 261 
 
783 richard 262 
#############################
263 
#         OUTPUT            #
264 
#############################
604 richard 265 
# SSHD rules if activate
612 richard 266 
if [ $SSH = on ]
604 richard 267 
	then
268 
	$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport ssh -m state --state ESTABLISHED -j ACCEPT
269 
fi
498 richard 270 
# On laisse tout sortir sur toutes les cartes sauf celle qui est connectée sur l'extérieur
271 
# Everything is allowed but traffic through outside network interface
272 
$IPTABLES -A OUTPUT ! -o $EXTIF -j ACCEPT
520 richard 273 
 
503 richard 274 
# On autorise les requêtes DNS vers les serveurs DNS identifiés
498 richard 275 
# Allow DNS requests to identified DNS servers
276 
$IPTABLES -A OUTPUT -o $EXTIF -d $DNSSERVERS -p udp --dport domain -m state --state NEW -j ACCEPT
783 richard 277 
 
615 richard 278 
# On autorise les requêtes HTTP sortantes
498 richard 279 
# HTTP requests are allowed
280 
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --dport http -j ACCEPT
783 richard 281 
 
615 richard 282 
# On autorise les requêtes NTP
498 richard 283 
# NTP requests are allowed
284 
$IPTABLES -A OUTPUT -o $EXTIF -p udp --dport ntp -j ACCEPT
783 richard 285 
 
503 richard 286 
# On autorise les requêtes ICMP (ping)
287 
# ICMP (ping) requests are allowed
288 
$IPTABLES -A OUTPUT -o $EXTIF -p icmp --icmp-type 8 -j ACCEPT
783 richard 289 
 
615 richard 290 
# On autorise les requêtes LDAP si un serveur externe est configué
291 
# LDAP requests are allowed if an external server is declared
292 
if [ $LDAP = on ]
293 
	then
694 franck 294 
	$IPTABLES -A OUTPUT -p tcp -d $LDAP_IP -m multiport --dports ldap,ldaps -m state --state NEW,ESTABLISHED -j ACCEPT
295 
	$IPTABLES -A OUTPUT -p udp -d $LDAP_IP -m multiport --dports ldap,ldaps -m state --state NEW,ESTABLISHED -j ACCEPT
296 
#	$IPTABLES -A INPUT  -p tcp -s $LDAP_IP -m multiports --sports ldap,ldaps -m state --state ESTABLISHED -j ACCEPT
297 
#	$IPTABLES -A INPUT  -p udp -s $LDAP_IP -m multiports --sports ldap,ldaps -m state --state ESTABLISHED -j ACCEPT
615 richard 298 
fi
783 richard 299 
 
300 
 
301 
#############################
302 
#       POSTROUTING         #
303 
#############################
498 richard 304 
# Traduction dynamique d'adresse en sortie
476 richard 305 
# Dynamic NAT on EXTIF
1 root 306 
$IPTABLES -A POSTROUTING -t nat -o $EXTIF -j MASQUERADE
307 
 
476 richard 308 
# Save all rules
1 root 309 
/etc/init.d/iptables save
310 
 
476 richard 311 
# End of script
1 root 312