Configure /proc

if [ -e /proc/sys/net/ipv4/ip_forward ]; then
    echo "1" > /proc/sys/net/ipv4/ip_forward
    echo -n "."
else
    echo "*** /proc/sys/net/ipv4/ip_forward does not exist!"
    echo "*** This is very bad (firewall probably won't work)!"
fi

echo "0" > /proc/sys/net/ipv4/conf/all/proxy_arp 
echo "1" > /proc/sys/net/ipv4/conf/eth0/proxy_arp
echo "1" > /proc/sys/net/ipv4/conf/eth1/proxy_arp