Initscript per firewall iptables su Debian

Creazione initscript

cat > /etc/init.d/firewall <<'EOFile'
#!/bin/sh -e
#
# v1.0 2005.12.16
# gabriele.vivinetto@rvmgroup.it

test $DEBIAN_SCRIPT_DEBUG && set -v -x

DESC="firewall"
CONFIG_DIR=/etc/firewall

test -d $CONFIG_DIR || {
  echo "$CONFIG_DIR missing, nothing to do."
  exit 1
}

start_firewall () {
  . $CONFIG_DIR/start.firewall || {
  echo "$CONFIG_DIR/start.firewall missing, not starting $DESC"
  exit 1
  }
}

stop_firewall () {
  . $CONFIG_DIR/stop.firewall || {
  echo "$CONFIG_DIR/stop.firewall missing, not stopping $DESC"
  exit 1
  }
}

case "$1" in
start)
  $0 restart
  ;;

stop)
  echo "Stopping $DESC:"
  stop_firewall
  echo "."
  ;;

restart)
  shift
  $0 stop
  sleep 1
  echo "Starting $DESC:"
  start_firewall
  echo "."
  ;;

*)
  echo "Usage: $0 {start|stop|restart}" >&2
  exit 1
  ;;
esac

exit 0
# vim:set ai sts=2 sw=2 tw=0:
EOFile

chmod 755 /etc/init.d/firewall
mkdir /etc/firewall

Creazione regole

Le regole sono contenute in due rulescripts:

• /etc/firewall/start.firewall: contiene le regole necessarie alla partenza del firewall. Questo files sarà eseguito dando l'opzione start all'initscript.

• /etc/firewall/stop.firewall: contiene le regole necessarie alla disattivazione di tutte le regole del firewall. Questo files sarà eseguito dando l'opzione stop all'initscript.

Se questi files non esistono, l'initscript terminerà.

Attivazione dell'initscript

Creaiamo i link di partena automatica dello script, che deve essere attivato dopo aver configurato le interfacce:

sudo update-rc.d firewall start 41 S . stop 89 0 6 .

Esempio di rulescripts

start.firewall

echo "Setting common variables... "

# ----------------------------------------------------------------------------
# EDIT THESE TO SUIT YOUR SYSTEM AND ISP.
# ------------------------------------------

        ANYWHERE="any/0"

        WAN0_IF="eth1"                          # Wan interface
        WAN0_IP="192.168.110.253"                       # WAN IP Address

        LAN0_IF="eth0"                          # Lan interface
        LAN0_IP="192.168.10.254"                # Lan IP Address
        LAN0_NET="192.168.10.0/24"              # Lan IP Network

        VPN0_IF="tun0"                          # LAN VPN interface
        VPN0_PT="40000"                         # LAN VPN interface
        VPN1_IF="tap0"                  # Roadwarriors VPN interface
        VPN1_PT="50000"                 # Roadwarriors VPN interface

        LAN0_SMTP_SERVER="192.168.10.100"
        LAN0_PROXY_SERVER="192.168.10.100"
        LAN0_DNS_SERVER="192.168.10.100"

        ADMIN_MAC_01="00:08:02:68:3A:7C"        # mnt.vvngrl intel lan


        #----------------------------------------------------------------------
        # NAMESERVERS
        #---------------------------

        NAMESERVER_1="194.20.8.1"
        NAMESERVER_2="194.20.8.4"
        NAMESERVER_3="151.99.125.2"

        # ---------------------------------------------------------------------
        # MISC
        # These parameters are unlikely to be changed
        # ---------------------------------------------

        UNPRIVPORTS="1024:65535"
        IPTABLES="/sbin/iptables"       # path and $IPTABLES executable

echo "Setting common variables DONE"

# ------------------------------------------------------------------------------
# Set Default Policies and restart IP Accounting
# -------------------------
echo "Setting Default Policies..."

#       /etc/init.d/ipac-ng restart

        $IPTABLES -P INPUT DROP
        $IPTABLES -P OUTPUT ACCEPT
        $IPTABLES -P FORWARD DROP
echo "Setting Default Policies done."


# -----------------------------------------------------------------------------
#Do NAT and Portmappings
# ------------------------

#echo "Configuring NAT"
        # ---------------------------------------------------------------------
        # Masquerade internal traffic.
        # ------------------------------

        #$IPTABLES -t nat -A POSTROUTING \
        #         -o $WAN0_IF  -d ! $LAN0_NET \
        #         -j SNAT --to-source $WAN0_IP


#echo "NAT done."


echo "Starting firewalling... "

# ------------------------------------------------------------------------------
# Unlock Administrative machines MAC Addressess
# ----------------------------------------------
        $IPTABLES -A INPUT \
                  -m mac --mac-source $ADMIN_MAC_01 \
                  -j ACCEPT

        $IPTABLES -A FORWARD \
                  -m mac --mac-source $ADMIN_MAC_01 \
                  -j ACCEPT

# ------------------------------------------------------------------------------
# Unlimited traffic within the loopback interface
# ----------------------------------------------

        # Unlimited traffic on the loopback interface.
        $IPTABLES -A INPUT  -i lo -j ACCEPT
        $IPTABLES -A OUTPUT -o lo -j ACCEPT

# ------------------------------------------------------------------------------
# INPUT Rules
# ----------------------------------------------

        # ---------------------------------------------------------------------
        # Ping
        # ---------------

                $IPTABLES -A INPUT   -p icmp --icmp-type 0 \
                          -j ACCEPT

                $IPTABLES -A INPUT  -p icmp --icmp-type 8 \
                          -j ACCEPT

        # ---------------------------------------------------------------------
        # SSH Server (22)
        # ---------------

        #WAN0
        $IPTABLES -A INPUT  -p tcp \
                  --sport $UNPRIVPORTS \
                  --dport 22  -j ACCEPT

        # ---------------------------------------------------------------------
        # VPN0
        # ----------------------

        $IPTABLES -A INPUT  -p udp  \
                  -i $WAN0_IF --sport $VPN0_PT \
                  -j ACCEPT

        $IPTABLES -A INPUT -i $VPN0_IF \
                  -j ACCEPT


        # ---------------------------------------------------------------------
        # VPN1
        # ----------------------

        $IPTABLES -A INPUT  -p udp  \
                  -i $WAN0_IF --sport $VPN1_PT \
                  -j ACCEPT

        $IPTABLES -A INPUT  -p udp  \
                  -i $WAN0_IF --dport $VPN1_PT \
                  -j ACCEPT

        $IPTABLES -A INPUT -i $VPN1_IF \
                  -j ACCEPT


        # ---------------------------------------------------------------------
        # Unlimited Lan Access
        # ---------------

        #LAN0
        $IPTABLES -A INPUT  -i $LAN0_IF \
                  -j ACCEPT

        # ---------------------------------------------------------------------
        # Allow established reply connections
        # ---------------

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

        # ---------------------------------------------------------------------
        #LOG Everything without limit
        # ---------------
        $IPTABLES -A INPUT \
                  -j LOG \
                  --log-level debug \
                  --log-prefix "Iptables INPUT Chain: "


        # ---------------------------------------------------------------------
        # Deny All Other input connections
        # ---------------

        $IPTABLES -A INPUT   \
                  -j DROP


# ------------------------------------------------------------------------------
# FORWARD Rules
# ----------------------------------------------

        # ------------------------------------------------------------------
        # Ping
        # ---------------

                $IPTABLES -A FORWARD -p icmp --icmp-type 8 \
                          -j ACCEPT


        # ------------------------------------------------------------------
        # SSH client (22)
        # ---------------

                $IPTABLES -A FORWARD -p tcp \
                          --dport 22 -j ACCEPT
        # ------------------------------------------------------------------
        # DNS
        # ------------------

        $IPTABLES -A FORWARD -p udp \
                  --dport 53 \
                  -s $LAN0_DNS_SERVER \
                  -j ACCEPT

        # ------------------------------------------------------------------
        # HTTP client (80)
        # ------------------

        $IPTABLES -A FORWARD -p tcp \
                  -d $ANYWHERE --dport 443 \
                  -s $LAN0_PROXY_SERVER --sport $UNPRIVPORTS \
                  -j ACCEPT

        # ------------------------------------------------------------------
        # HTTPS client (443)
        # ------------------

        $IPTABLES -A FORWARD -p tcp \
                  -d $ANYWHERE --dport 80 \
                  -s $LAN0_PROXY_SERVER --sport $UNPRIVPORTS \
                  -j ACCEPT

        # ------------------------------------------------------------------
        # SMTP client (smtp 25)
        # ----------------
                $IPTABLES -A FORWARD -p tcp \
                          --sport $UNPRIVPORTS \
                          -s $LAN0_SMTP_SERVER --dport 25 \
                          -j ACCEPT

        # ------------------------------------------------------------------
        # IMAP4 client (imap4 143)
        # ----------------
        #       $IPTABLES -A FORWARD -p tcp -o $WAN0_IF \
        #                 --sport $UNPRIVPORTS \
        #                 -d $POP3_SERVER --dport 143 \
        #                 -j ACCEPT

        # ------------------------------------------------------------------
        # IMAP4s client (imap4 993)
        # ----------------
        #       $IPTABLES -A FORWARD -p tcp -o $WAN0_IF \
        #                 --sport $UNPRIVPORTS \
        #                 -d $POP3_SERVER --dport 993 \
        #                 -j ACCEPT


        # ------------------------------------------------------------------
        # VPN clients through $VPN0_IF (OpenVpn Limbiate)
        # ----------------

        $IPTABLES -A FORWARD -i $VPN0_IF \
                  -j ACCEPT

        $IPTABLES -A FORWARD -o $VPN0_IF \
                  -j ACCEPT

        # ------------------------------------------------------------------
        # VPN1
        # ----------------

        $IPTABLES -A FORWARD -i $VPN1_IF \
                  -j ACCEPT

        $IPTABLES -A FORWARD -o $VPN1_IF \
                  -j ACCEPT


        # ---------------------------------------------------------------------
        # Allow all established reply connections
        # ----------------------

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

        # ---------------------------------------------------------------------
        #LOG Everything without limit
        # ---------------
        $IPTABLES -A FORWARD \
                  -j LOG \
                  --log-level debug \
                  --log-prefix "Iptables FORWARD Chain: "

        # ---------------------------------------------------------------------
        # Deny All Other forward connections
        # ---------------

        $IPTABLES -A FORWARD   \
                  -j DROP

echo "Firewalling done"

stop.firewall

# -----------------------------------------------------------------------------
# Clean all tables and rules
# ------------------------------

IPTABLES="/sbin/iptables"

echo "Flushing all tables and rules... "

# reset the default policies in the filter table.
#
$IPTABLES -P INPUT ACCEPT
$IPTABLES -P FORWARD ACCEPT
$IPTABLES -P OUTPUT ACCEPT

# reset the default policies in the nat table.
#
$IPTABLES -t nat -P PREROUTING ACCEPT
$IPTABLES -t nat -P POSTROUTING ACCEPT
$IPTABLES -t nat -P OUTPUT ACCEPT

# reset the default policies in the mangle table.
#
$IPTABLES -t mangle -P PREROUTING ACCEPT
$IPTABLES -t mangle -P OUTPUT ACCEPT

# flush all the rules in the filter nat and mangle tables.
#
$IPTABLES -F
$IPTABLES -t nat -F
$IPTABLES -t mangle -F

# erase all chains that's not default in filter and nat table.
#
$IPTABLES -X
$IPTABLES -t nat -X
$IPTABLES -t mangle -X

# -----------------------------------------------------------------------------
#Do NAT and Portmappings
# ------------------------

#echo "Configuring NAT"

        # ---------------------------------------------------------------------
        # Masquerade internal traffic.
        # ------------------------------

        #$IPTABLES -t nat -A POSTROUTING \
        #         -o $WAN0_IF  -d ! $LAN0_NET \
        #         -j SNAT --to-source $WAN0_IP

#echo "NAT done."