Problem with gateway and ipfw in FreeBSD 5.2

[Tony Liew]

Hi,

Currently I am trying out FreeBSD 5.2.

SDSL modem
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FreeBSD Router
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Internal network

My problem, from FreeBSD I can ping outside and inside network.
from Internal network, I can ping internal interface and external 
interface of FreeBSD Router. But I cannot ping the modem IP address so 
goes public DNS server on the internet.

I have in my KERNEL:
options   BRIDGE
options   DIVERT
options   IPFIREWALL
options   IPFIREWALL_DEFAULT_TO_ACCEPT

rc.conf
gateway_enable="YES"
defaultrouter="<modem ip>"
firewall_enable="YES"
firewall_type="OPEN"
natd_interface="<external interface>"
natd_enable="YES"
router_enable="YES"

sysctl.conf

net.link.ether.bridge.enable=1
net.link.ether.bridge.config=external interface, internal interface
net.link.ether.bridge.ipfw=1


client on the internal network cannot connect to the internet. Any 
suggestion?

Thanks a lot.

Regards,
Tony Liew