FreeBSD router: Can my internet provider detect my home network?

[Rob]

Hi,

I plan to have a FreeBSD (4.9 stable) system serving as a router
between my provider and a set of my home computers connected
via a home network.

My provider does not really like this, but I don't care so much,
as long as s/he cannot detect (too easily) my home network.

My plan is to use the following setup in my rc.conf:
    gateway_enable="YES"
    natd_enable="YES"
    natd_interface="rl0"
    firewall_enable="YES"
    firewall_type="open"

(with, of course, the proper options compiled into the kernel).

Is it correct, that the combination of firewall and natd divert
all requests and thus hide the home network for my provider?
Are requests from all other networked home PC's done on behalf of
the router, so that my provider will only see requests from my router?

Or do I need some better (firewall?) configuration for this?

Thanks,
Rob.