NPF port forward

[William Ross <williamrossmbsw%gmail.com@localhost>]

I'm trying to get all packets sent by one specific machine (with IP 10.0.0.53) to port 389 on my NetBSD box to be redirected to port 3890 (also on my NetBSD box).
My /etc/npf.conf is below and it looks like it should work, but has no effect. When I access port 389 from 10.0.0.53 I still get the service running on port 389, rather than the one on port 3890. Can anyone suggest changes I can make to the config, or am I misusing NAT?


map pcn0 dynamic 127.0.0.1 port 3890 <- pcn0 pass from 10.0.0.53 port 389
group (name "internal", interface pcn0) {
        pass all
}
group (default) {
        pass final on lo0 all
        block all
}


Thanks,

Will