Hi everyone I'm a bit new to iptables so please bear with me on this one ;)

I wrote a small firewall that basicaly nats users through my gateway
machine only allowing certain hosts on my network Web DNS and Mail access.

This section works fine.

But I also want to port forward any connections from outside to port 800
to a host running inside my LAN.
I added a rule in the PREROUTING table to do this.

But it seems that no connection gets forwarded.

If I set my default policies to ACCEPT and add the PREROUTING rule it
actualy does the port forwarding correctly.

I attached a copy of the firewall I wrote with this message.

Please can someone have a look through it for me cause I'm sure I'm just
missing something.

Kind Regards Julian.