[pf4freebsd] Using authpf

[novocaine at free.fr]

First, I'd like to thank all the contributers of the port of pf to FreeBSD.

I am trying to use authpf on -CURRENT, without success so far. I'd like to
enable ftp access for user "os" using authpf.

In /usr/local/etc/pf.conf, I have :
...
set block-policy return
set loginterface $ext_if
scrub in all

nat-anchor authpf
rdr-anchor authpf
binat-anchor authpf

<rules>

anchor authpf in on $ext_if

I have an empty file /usr/local/etc/authpf/authpf.conf and 
/usr/local/etc/authpf/users/os/authpf.rules reads
$ext_if="tun0"
pass in quick on $ext_if proto tcp from $user_ip to any port http

I also try to set /usr/local/sbin/authpf as os' shell (as described on
authpf(8)) but it doesn't seem to work. I had to add authpf to /etc/shells.

Am I doing something wrong?

Thanks,

                          - Olivier