Firewall scripting - loops howto

[mdevin@ozemail.com.au]

I am trying to make my firewall do a very basic loop.

Here are the relevant parts of the script.
------------------------------
IPADDR=`ifconfig $EXT_IF | grep inet | cut -d : -f 2 | cut -d \  -f 1`

NAMESERVERS=`grep nameserver /etc/resolv.conf | cut -d \  -f 2` # Stores 2 DNSs

for DNS_ADDRESS in $NAMESERVERS ;
	do
	iptables -A OUTPUT -o $EXT_IF -p udp -s $IPADDR --sport $UNPRIVPORTS \
			-d $DNS_ADDRESS --dport $DNS_PORT -j ACCEPT
	iptables -A OUTPUT -o $EXT_IF -p tcp -s $IPADDR --sport $UNPRIVPORTS \
			-d $DNS_ADDRESS --dport $DNS_PORT -j ACCEPT
	iptables -A INPUT -i $EXT_IF -p udp -s DNS_ADDRESS --sport $DNS_PORT \
			-d $IPADDR --dport $UNPRIVPORTS -j ACCEPT
	iptables -A INPUT -i $EXT_IF -p tcp -s DNS_ADDRESS --sport $DNS_PORT \
			-d $IPADDR --dport $UNPRIVPORTS -j ACCEPT
	done
------------------------------
I have never written a script with a loop.  The above seems to hang.
what is wrong with it?

Regards.
Mark.