> > can it be done? if so, how would i go about it?
> 
> Simply remove options IPFORWARDING and options GATEWAY from the config file.

Wrong.  Even with IPFORWARDING and GATEWAY off NetBSD (and all BSD IP
stacks by default including BSDI 1.1 and 2.0) still pass source routed packets.
You have to modify ip_dooptions() in ip_input.c.  At the bottom of the
function where it says 

	if (forward) {
		ip_forward(m, 1);
		return (1);
	}

Change it to look something like:

	if (forward) {
#ifndef SROKAY
		m_free(m);
#else
		ip_forward(m, 1);
#endif
		return (1);
	}