IF=$1
PUBIP=$2
MASK=$3
PRIVIP=$4

/sbin/ip addr add $PUBIP/$MASK dev $IF
#/sbin/iptables -t nat -A PREROUTING -i $IF -d $PUBIP -j DNAT --to $PRIVIP 
#/sbin/iptables -t nat -A POSTROUTING -o $IF -s $PRIVIP -j SNAT --to $PUBIP
/sbin/iptables -t nat -A PREROUTING  -d $PUBIP -j DNAT --to $PRIVIP 
/sbin/iptables -t nat -A POSTROUTING  -s $PRIVIP -j SNAT --to $PUBIP
if [ $# -eq 5 ];then
TABLE=$5
/sbin/ip rule add from $PRIVIP table $TABLE
fi

./pubip-up eth0 10.172.0.42 24 192.168.222.42

/sbin/brctl addbr vbr2
/sbin/brctl setfd vbr2 0
/sbin/ifconfig vbr2 192.168.222.1 netmask 255.255.255.0 promisc up
/sbin/iptables -t nat -A POSTROUTING -o vbr0 -j MASQUERADE

./vbr2-up

/sbin/iptables -t nat -D POSTROUTING -o vbr0 -j MASQUERADE
/sbin/ifconfig vbr2 down
/sbin/brctl delbr vbr2

./vbr2-down