help setting up natd and ipfw on freebsd5.2.1

[asolomon15]

Hello all,
I tried to setup natd on my  fbsd 5.2.1 box and fbsd 4.10 box with no 
luck.   What I wanted to do was to setup a gateway for my internal 
network to my cable provider.  On my server box I have two ethernet card 
dc0 pointing to cable modem and dc1 pointing to hub so that the other 
computers may connect with my bsd gateway.  I managed recompile the 
kernel with options IPFIREWALL and IPDIVERT and  kernel  compiled 
successfully. 

Then I add natd, gateway and firewall to my rc.conf file
gateway_enable="YES"
natd_enable="YES'
natd_interface="dc0"
firewall_enable="YES"
firewall_type="/etc/rc.firewall"

I wanted to ping an external and internal hosts to see if this 
configuration worked so   I really didn't want to have the firewall up 
so I added these 3 lines to my rc.firewall file

/sbin/ipfw  -f flush
/sbin/ipfw add divert  natd all from any to any via dc0
/sbin/ipfw add pass from any to any

I wasn't able to ping any host inside or outside of my computer. When I 
disabled the ipfw I was able to ping them.   Also I wanted to make sure 
if I needed to configure a dns server on my firewall to allow such 
services like http and ftp for internal hosts.   I know that there are 
more sophisticated ipfw setups but I wanted to just get the natd setup 
so I could concentrate on the firewall later on.  


Thanks if you can help
Antoine W. Solomon