[Samba] security = none?

[dionysus]

hey guys. I am running a samba server on my machine at home, which has
two other machines on it - both running windows, one's mine and one's
my flatmates. Since I am running samba on a trusted network (and I do
have the hosts allow rule restricting access so that when I connect to
the net people can't just start using my samba server), I am wanting
to essentially remove the security feature (well, for that reason and
the fact that I can't get the bloody thing to work in either user or
security mode). I have tried setting null passswords = true, but this
doesn't seem to do anything. How can I just turn off security?

TIA

-d