Subversion Repositories ALCASAR

#!/bin/bash

# $Id: alcasar-iptables.sh 1294 2014-01-12 23:03:00Z richard $

# Script de mise en place des regles du parefeu d'Alcasar (mode normal)

# This script write the netfilter rules for ALCASAR

# Rexy - 3abtux - CPN

#

# Reminders

# There are four channels for log :

#	1 tracability of the consultation equipment with The 'Netflow' kernel module (iptables target = NETFLOW);

#	2 protection of ALCASAR with the Ulog group 1 (default group) 

#	3 SSH on ALCASAR with the Ulog group 2;

#	4 extern access attempts on ALCASAR with the Ulog group 3.

# The bootps/dhcp (67) port is always open on tun0/eth1 by coova 

conf_file="/usr/local/etc/alcasar.conf"

private_ip_mask=`grep PRIVATE_IP= $conf_file|cut -d"=" -f2`

private_ip_mask=${private_ip_mask:=192.168.182.1/24}

PRIVATE_IP=`echo $private_ip_mask | cut -d"/" -f1`			# ALCASAR LAN IP address

private_network=`/bin/ipcalc -n $private_ip_mask|cut -d"=" -f2`		# LAN IP address (ie.: 192.168.182.0)

private_prefix=`/bin/ipcalc -p $private_ip_mask|cut -d"=" -f2`		# LAN prefix (ie. 24)

PRIVATE_NETWORK_MASK=$private_network/$private_prefix			# Lan IP address + prefix (192.168.182.0/24)

public_ip_mask=`grep PUBLIC_IP= $conf_file|cut -d"=" -f2`		# ALCASAR WAN IP address

PUBLIC_IP=`echo $public_ip_mask | cut -d"/" -f1`

dns1=`grep DNS1= $conf_file|cut -d"=" -f2`				# first public DNS server

dns1=${dns1:=208.67.220.220}

dns2=`grep DNS2= $conf_file|cut -d"=" -f2`				# second public DNS server

dns2=${dns2:=208.67.222.222}

DNSSERVERS="$dns1,$dns2"						# first and second DNS IP servers addresses

PROTOCOLS_FILTERING=`grep PROTOCOLS_FILTERING= $conf_file|cut -d"=" -f2`	# Network protocols filter (on/off)

PROTOCOLS_FILTERING=${PROTOCOLS_FILTERING:=off}

DNS_FILTERING=`grep DNS_FILTERING= $conf_file|cut -d"=" -f2`		# DNS and URLs filter (on/off)

DNS_FILTERING=${DNS_FILTERING:=off}

BL_IP_CAT="/usr/local/share/iptables-bl"				# categories files of the BlackListed IP

QOS=`grep QOS= $conf_file|cut -d"=" -f2`				# QOS (on/off)

QOS=${QOS:=off}

SSH=`grep SSH= $conf_file|cut -d"=" -f2`				# sshd active (on/off)

SSH=${SSH:=off}

SSH_ADMIN_FROM=`grep SSH_ADMIN_FROM= $conf_file|cut -d"=" -f2`

SSH_ADMIN_FROM=${SSH_ADMIN_FROM:="0.0.0.0/0.0.0.0"}			# WAN IP address to reduce ssh access (all ip allowed on LAN side)

LDAP=`grep LDAP= $conf_file|cut -d"=" -f2`				# LDAP external server active (on/off)

LDAP=${LDAP:=off}

LDAP_IP=`grep LDAP_IP= $conf_file|cut -d"=" -f2`			# WAN IP address to reduce LDAP WAN access (all ip allowed on LAN side)

LDAP_IP=${LDAP_IP:="0.0.0.0/0.0.0.0"}

EXTIF="eth0"

INTIF="eth1"

TUNIF="tun0"								# listen device for chilli daemon

IPTABLES="/sbin/iptables"

# loading of NetFlow probe (ipt_NETFLOW kernel module)

modprobe ipt_NETFLOW destination=127.0.0.1:2055

# Effacement des règles existantes

# Flush all existing rules

$IPTABLES -F

$IPTABLES -t nat -F

$IPTABLES -t mangle -F

$IPTABLES -F INPUT

$IPTABLES -F FORWARD

$IPTABLES -F OUTPUT

# Suppression des chaines utilisateurs sur les tables filter et nat

# Flush non default rules on filter and nat tables

$IPTABLES -X

$IPTABLES -t nat -X

# Stratégies par défaut

# Default policies

$IPTABLES -P INPUT DROP

$IPTABLES -P FORWARD DROP

$IPTABLES -P OUTPUT DROP

$IPTABLES -t nat -P PREROUTING ACCEPT

$IPTABLES -t nat -P POSTROUTING ACCEPT

$IPTABLES -t nat -P OUTPUT ACCEPT

# destruction de tous les SET

# destroy all the SET

ipset destroy

# Création et peuplement du SET alcasar_ip_blocked

# creation and first populating of alcasar_ip_blocked SET

ipset create alcasar_ip_blocked hash:net hashsize 1024

if [ -s /usr/local/etc/alcasar-ip-blocked ]; then 

	while read ip_line

	do

		ip_on=`echo $ip_line|cut -b1`

		if [ $ip_on != "#" ]

		then	

			ip_blocked=`echo $ip_line|cut -d" " -f1`

			ipset add alcasar_ip_blocked $ip_blocked

		fi

	done < /usr/local/etc/alcasar-ip-blocked

fi

# Création et initialisation du SET authenticated_ip (dynamiquement peuplé par les scripts conup/condown)

# creation and initialization of authenticated_ip_ SET (populated dynamicly by conup/condown scripts)

ipset create authenticated_ip hash:net hashsize 1024

OLDIFS=$IFS

IFS=$'\n'

for equipment in `/usr/sbin/chilli_query list |grep -v "\.0\.0\.0"`

do

	active_ip=`echo $equipment |cut -d" " -f2`

	active_session=`echo $equipment |cut -d" " -f5`

	if [[ $(expr $active_session) -eq 1 ]]

	then

		ipset add authenticated_ip $active_ip

	fi

done

IFS=$OLDIFS

# Création et peuplement du SET blacklist_ip_blocked

# creation and first populating of blacklist_ip_blocked SET

# wait for a better blacklist adapt process 

#ipset create blacklist_ip_blocked hash:net hashsize 1024

#cd $BL_IP_CAT

#for category in `ls -1 | cut -d"@" -f1`

#do

#	while read ip_blocked

#	do

#		ipset add blacklist_ip_blocked $ip_blocked

#	done < $BL_IP_CAT/$category

#done

#############################

#       PREROUTING          #

#############################

# Marquage (et journalisation) des paquets qui tentent d'accéder directement à DansGuardian pour pouvoir les rejeter en INPUT

# mark (and log) the dansguardian bypass attempts in order to DROP them in INPUT rules

$IPTABLES -A PREROUTING -t nat -i $TUNIF -p tcp -d $PRIVATE_IP -m tcp --dport 8080 -j ULOG --ulog-prefix "RULE direct-proxy -- DENY "

$IPTABLES -A PREROUTING -t mangle -i $TUNIF -d $PRIVATE_IP -p tcp -m tcp --dport 8080 -j MARK --set-mark 1

# Marquage (et journalisation) des paquets qui tentent d'accéder directement au port udp 54 pour pouvoir les rejeter en INPUT

# Mark (and log) the udp 54 direct attempts to REJECT them in INPUT rules

# Remarque : Ce port n'est ouvert que lorsque le filtrage est activé

# Remark : this port is only open when filtering is on

# $IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -d $PRIVATE_IP -m udp --dport 54 -j ULOG --ulog-prefix "RULE DNS-proxy -- DENY "

$IPTABLES -A PREROUTING -t mangle -i $TUNIF -d $PRIVATE_IP -p tcp --dport 54 -j MARK --set-mark 2

# Si le filtrage DNS est activé, redirection des flux DNS vers le port 54 (dns+blackhole) sauf pour les IP en exceptions 

# If DNS filter is on, redirect DNS request to udp 54 (dns+blackhole) except for exception IP addresses

if [ $DNS_FILTERING = on ]; then

	# Compute exception IP

	nb_exceptions=`wc -l /usr/local/etc/alcasar-filter-exceptions | cut -d" " -f1`

	if [ $nb_exceptions != "0" ]

	then

		while read ip_exception 

		do

			$IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -s $ip_exception -d $PRIVATE_IP --dport domain -j ACCEPT

		done < /usr/local/etc/alcasar-filter-exceptions

	fi

		$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport domain -j REDIRECT --to-port 54

fi

# Redirection des requêtes HTTP des IP admin bannies vers ALCASAR (page 'accès interdit')

# Redirect HTTP requests of admin banned ip to ALCASAR (access deny window)

$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK -m set --match-set alcasar_ip_blocked dst -p tcp --dport http -j REDIRECT --to-port http

# Redirection des requêtes HTTP des IP de la blacklist vers ALCASAR (page 'accès interdit')

# Redirect HTTP requests of blacklist ip to ALCASAR (access deny window)

#if [ $DNS_FILTERING = on ]; then

#$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK -m set --match-set blacklist_ip_blocked dst -p tcp --dport http -j REDIRECT --to-port 80

#fi

# Redirection des requêtes HTTPS des IP sans utilisateurs authentifiés vers ALCASAR (page d'interception)

# Redirect HTTPS requests of IP that don't have authenticate user to ALCASAR (intercept page)

$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK -m set ! --match-set authenticated_ip src ! -d $PRIVATE_IP -p tcp --dport https -j REDIRECT --to-port https

# Journalisation des requètes HTTP vers Internet (seulement les paquets SYN) - Les autres protocoles sont journalisés en FORWARD par netflow

## Log HTTP requests to Internet (only syn packets) - Other protocols are log in FORWARD by netflow

$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 "

# Redirection des requêtes HTTP sortantes vers DansGuardian (proxy transparent)

# Redirect outbound HTTP requests to DansGuardian (transparent proxy)

$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK ! -d $PRIVATE_IP -p tcp --dport http -j REDIRECT --to-port 8080

# Redirection des requêtes NTP vers le serveur NTP local

# Redirect NTP request in local NTP server

$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK ! -d $PRIVATE_IP -p udp --dport ntp -j REDIRECT --to-port 123

#############################

#         INPUT             #

#############################

# Tout passe sur loopback

# accept all on loopback

$IPTABLES -A INPUT -i lo -j ACCEPT

$IPTABLES -A OUTPUT -o lo -j ACCEPT

# Rejet des demandes de connexions non conformes (FIN-URG-PUSH, XMAS, NullScan, SYN-RST et NEW not SYN)

# Drop non standard connexions (FIN-URG-PUSH, XMAS, NullScan, SYN-RST et NEW not SYN)

$IPTABLES -A INPUT -p tcp --tcp-flags FIN,URG,PSH FIN,URG,PSH -j DROP

$IPTABLES -A INPUT -p tcp --tcp-flags ALL ALL -j DROP

$IPTABLES -A INPUT -p tcp --tcp-flags ALL NONE -j DROP

$IPTABLES -A INPUT -p tcp --tcp-flags SYN,RST SYN,RST -j DROP

$IPTABLES -A INPUT -p tcp -m tcp ! --syn -m state --state NEW -j DROP

# On rejette les trame en broadcast et en multicast sur EXTIF (évite leur journalisation)

# Drop broadcast & multicast on EXTIF to avoid log 

$IPTABLES -A INPUT -i $EXTIF -m addrtype --dst-type BROADCAST,MULTICAST -j DROP

# On autorise les retours de connexions légitimes par INPUT

# Conntrack on INPUT

$IPTABLES -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

# On interdit les connexions directes au port utilisé par DansGuardian (8080). Les packets concernés ont été marqués et loggués dans la table mangle (PREROUTING)

# Deny direct connections on DansGuardian port (8080). The concerned paquets are marked and logged in mangle table (PREROUTING)

$IPTABLES -A INPUT -i $TUNIF -p tcp --dport 8080 -m mark --mark 1 -j REJECT --reject-with tcp-reset

# Autorisation des connexions légitimes à DansGuardian 

# Allow connections for DansGuardian

$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -p tcp --dport 8080 -m state --state NEW --syn -j ACCEPT

# On interdit les connexions directes au port UDP 54. Les packets concernés ont été marqués dans la table mangle (PREROUTING)

# Deny direct connections on UDP 54. The concerned paquets are marked in mangle table (PREROUTING)

$IPTABLES -A INPUT -i $TUNIF -p udp --dport 54 -m mark --mark 2 -j REJECT --reject-with icmp-port-unreachable

# autorisation des connexion légitime à DNSMASQ (avec blackhole)

# Allow connections for DNSMASQ (with blackhole)

$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport 54 -j ACCEPT

# Accès direct aux services internes

# Internal services access

$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport domain -j ACCEPT	# DNS non filtré # DNS without blackhole

$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p icmp --icmp-type 8 -j ACCEPT	# Réponse ping # ping responce

$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p icmp --icmp-type 0 -j ACCEPT	# Requête  ping # ping request

$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

$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

$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

$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

# SSHD rules if activate 

if [ $SSH = on ]

	then

	$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"

	$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport ssh -j ACCEPT

	$IPTABLES -A INPUT -i $EXTIF -s $SSH_ADMIN_FROM -d $PUBLIC_IP -p tcp --dport ssh -m state --state NEW --syn -j ULOG --ulog-nlgroup 2 --ulog-prefix "RULE ssh-from-WAN -- ACCEPT"

	$IPTABLES -A INPUT -i $EXTIF -s $SSH_ADMIN_FROM -d $PUBLIC_IP -p tcp --dport ssh -m state --state NEW -j ACCEPT

fi

# Insertion de règles locales

# Here, we add local rules (i.e. VPN from Internet)

if [ -f /usr/local/etc/alcasar-iptables-local.sh ]; then

        . /usr/local/etc/alcasar-iptables-local.sh

fi

# Journalisation et rejet des connexions (autres que celles autorisées) effectuées depuis le LAN

# Deny and log on INPUT from the LAN

$IPTABLES -A INPUT -i $TUNIF -m state --state NEW -j ULOG --ulog-prefix "RULE rej-int -- REJECT "

$IPTABLES -A INPUT -i $TUNIF -p tcp -j REJECT --reject-with tcp-reset

$IPTABLES -A INPUT -i $TUNIF -p udp -j REJECT --reject-with icmp-port-unreachable

# interdiction d'accès à INTIF (n'est utile que lorsque chilli est arrêté).

# Reject INTIF access (only when chilli is down)

$IPTABLES -A INPUT -i $INTIF -j ULOG --ulog-prefix "RULE Protect1 -- REJECT "

$IPTABLES -A INPUT -i $INTIF -j REJECT

# Journalisation et rejet des connexions initiées depuis le réseau extérieur (test des effets du paramètre --limit en cours)

# On EXTIF, the access attempts are log in channel 2 (we should test --limit option to avoid deny of service)

$IPTABLES -A INPUT -i $EXTIF -m state --state NEW -j ULOG --ulog-nlgroup 3 --ulog-qthreshold 10 --ulog-prefix "RULE rej-ext -- DROP"

#############################

#        FORWARD            #

#############################

# Rejet des requêtes DNS vers Internet

# Deny forward DNS

$IPTABLES -A FORWARD -i $TUNIF -p udp --dport domain -j REJECT --reject-with icmp-port-unreachable

$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport domain -j REJECT --reject-with tcp-reset

# Blocage des IPs du SET alcasar_ip_blocked

# Deny IPs of the SET alcasar_ip_blocked 

$IPTABLES -A FORWARD -i $TUNIF -m set --match-set alcasar_ip_blocked dst -p icmp -j REJECT --reject-with icmp-port-unreachable

$IPTABLES -A FORWARD -i $TUNIF -m set --match-set alcasar_ip_blocked dst -p udp -j REJECT --reject-with icmp-port-unreachable

$IPTABLES -A FORWARD -i $TUNIF -m set --match-set alcasar_ip_blocked dst -p tcp -j REJECT --reject-with tcp-reset

# Blocage des IPs du SET blacklist_ip_blocked

# Deny IPs of the SET blacklist_ip_blocked 

#if [ $DNS_FILTERING = on ]; then

#	$IPTABLES -A FORWARD -i $TUNIF -m set --match-set blacklist_ip_blocked -p icmp -j REJECT --reject-with icmp-port-unreachable

#	$IPTABLES -A FORWARD -i $TUNIF -m set --match-set blacklist_ip_blocked dst -p udp -j REJECT --reject-with icmp-port-unreachable

#	$IPTABLES -A FORWARD -i $TUNIF -m set --match-set blacklist_ip_blocked -p tcp -j REJECT --reject-with tcp-reset

#fi

# Autorisation des retours de connexions légitimes

$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT

#  If protocols filter is activate 

if [ $PROTOCOLS_FILTERING = on ]; then

	# Compute exception IP (IP addresses that shouldn't be filtered)

	nb_exceptions=`wc -l /usr/local/etc/alcasar-filter-exceptions | cut -d" " -f1`

	if [ $nb_exceptions != "0" ]

	then

		while read ip_exception 

		do

#			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j ULOG --ulog-prefix "RULE IP-exception -- ACCEPT "

			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j NETFLOW

			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j ACCEPT

		done < /usr/local/etc/alcasar-filter-exceptions

	fi

	# Compute uamallowed IP (IP address of equipments connected between ALCASAR and Internet (DMZ, own servers, ...) 

	nb_uamallowed=`wc -l /usr/local/etc/alcasar-uamallowed | cut -d" "  -f1`

	if [ $nb_uamallowed != "0" ]

	then

		while read ip_allowed_line 

		do

			ip_allowed=`echo $ip_allowed_line|cut -d"\"" -f2`

#			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j ULOG --ulog-prefix "RULE IP-allowed -- ACCEPT "

			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j NETFLOW

			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j ACCEPT

		done < /usr/local/etc/alcasar-uamallowed

	fi

	# Autorisation des protocoles non commentés

	# Allow non comment protocols

	while read svc_line

	do

		svc_on=`echo $svc_line|cut -b1`

		if [ $svc_on != "#" ]

		then	

			svc_name=`echo $svc_line|cut -d" " -f1`

			svc_port=`echo $svc_line|cut -d" " -f2`

			if [ $svc_name = "icmp" ]

			then

				$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p icmp -j NETFLOW

				$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p icmp -j ACCEPT 

			else

#				$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p tcp --dport $svc_port -m state --state NEW -j ULOG --ulog-prefix "RULE F_TCP-$svc_name -- ACCEPT "

				$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p tcp --dport $svc_port -m state --state NEW -j NETFLOW

				$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p tcp --dport $svc_port -m state --state NEW -j ACCEPT

#				$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p udp --dport $svc_port -m state --state NEW -j ULOG --ulog-prefix "RULE F_UDP-$svc_name -- ACCEPT "

				$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p udp --dport $svc_port -m state --state NEW -j NETFLOW

				$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p udp --dport $svc_port -m state --state NEW -j ACCEPT

			fi

		fi

	done < /usr/local/etc/alcasar-services

	# Rejet explicite des autres protocoles

	# reject the others protocols

#	$IPTABLES -A FORWARD -i $TUNIF -j ULOG --ulog-prefix "RULE F_filter -- REJECT "

	$IPTABLES -A FORWARD -i $TUNIF -p tcp -j REJECT --reject-with tcp-reset

	$IPTABLES -A FORWARD -i $TUNIF -p udp -j REJECT --reject-with icmp-port-unreachable

	$IPTABLES -A FORWARD -i $TUNIF -p icmp -j REJECT 

fi

#  If QOS is activate  #

if [ $QOS = on ] && [ -e /usr/local/etc/alcasar-iptables-qos.sh ]; then

	. /usr/local/etc/alcasar-iptables-qos.sh 	

fi

# Autorisation des connections sortant du LAN  

# Allow forward connections with log

#$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -m state --state NEW -j ULOG --ulog-prefix "RULE F_all -- ACCEPT "

$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -m state --state NEW -j NETFLOW

$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -m state --state NEW -j ACCEPT

#############################

#         OUTPUT            #

#############################

# On laisse tout sortir sur toutes les cartes sauf celle qui est connectée sur l'extérieur

# Everything is allowed but traffic through outside network interface

$IPTABLES -A OUTPUT ! -o $EXTIF -j ACCEPT

# On autorise les requêtes DNS vers les serveurs DNS identifiés 

# Allow DNS requests to identified DNS servers

$IPTABLES -A OUTPUT -o $EXTIF -d $DNSSERVERS -p udp --dport domain -m state --state NEW -j ACCEPT

# On autorise les requêtes HTTP sortantes

# HTTP requests are allowed

$IPTABLES -A OUTPUT -o $EXTIF -p tcp --dport http -j NETFLOW

$IPTABLES -A OUTPUT -o $EXTIF -p tcp --dport http -j ACCEPT

# On autorise les requêtes FTP 

# FTP requests are allowed

modprobe ip_conntrack_ftp

$IPTABLES -A OUTPUT -o $EXTIF -p tcp --dport ftp -j ACCEPT

$IPTABLES -A OUTPUT -o $EXTIF -m state --state ESTABLISHED,RELATED -j ACCEPT

# On autorise les requêtes NTP 

# NTP requests are allowed

$IPTABLES -A OUTPUT -o $EXTIF -p udp --dport ntp -j ACCEPT

# On autorise les requêtes ICMP (ping) 

# ICMP (ping) requests are allowed

$IPTABLES -A OUTPUT -o $EXTIF -p icmp --icmp-type 8 -j ACCEPT

# On autorise les requêtes LDAP si un serveur externe est configué

# LDAP requests are allowed if an external server is declared

if [ $LDAP = on ]

	then

	$IPTABLES -A OUTPUT -p tcp -d $LDAP_IP -m multiport --dports ldap,ldaps -m state --state NEW,ESTABLISHED -j ACCEPT

	$IPTABLES -A OUTPUT -p udp -d $LDAP_IP -m multiport --dports ldap,ldaps -m state --state NEW,ESTABLISHED -j ACCEPT

fi

#############################

#       POSTROUTING         #

#############################

# Traduction dynamique d'adresse en sortie

# Dynamic NAT on EXTIF

$IPTABLES -A POSTROUTING -t nat -o $EXTIF -j MASQUERADE

# Save all rules

/etc/init.d/iptables save

# End of script