what am i missing on my firewall?

["McKevitt, Larry" <lmckevitt@hjth.com>]

All:
I'm trying to set up a firewall that also routes. 
So, from the 'doze box, the OBSD internal nic is the default gateway.  OBSD
2.8 i386.  
My ipf.rules is "pass in from any to any", "pass out from any to any" and my
ipnat.rules is "map fxp0 172.16.1.1/16  -> 209.85.xxx.xxx/24 portmap tcp/udp
1000:60000" and "map fxp0 172.16.1.1/16  -> 209.85.xxx.xxx/24 ".  fxp0 is
the outside nic.  
Once I reset my default gateway to my inside nic on the 'doze box, I lose
access to the world.  From the OBSD box, I can ping, telnet, etc..., so I
know I'm ok there.  Also, the rc.conf and sysctl.conf are set up properly.
Do I need gated running?  When I do try to access the Internet from the
'doze box, I do see the natting taking place with "ipnat -l", but the web
pages don't come thru.  TIA.
-larry-

ps:  anyone know anyone who went to devry?  just wondering.  thanks.