I tried this and I'm afraid it doesn't work. I can't ping anymore,
neither from my own box nor from the firewall. This setup is basically
what I also found in the books I have, I guess. :-(
DHCP works (i.e. my box gets an IP from the DHCP daemon on the
firewall) and I can see maradns receiving requests from localhost (the
firewall) and from the int_if (my box) when I try to ping something.
It's all blocked by the firewall, though.
I don't think it should matter but the only "special" thing about my
setup is that my external IP is on 192.168.1.0/24. Yes, that's my
*external* network. No more IPv4 address shortages for my ISP. :-)
Please also see my next reply.