Установлена OpenBSD 3.5 и включен pf
Конфиг
#       $OpenBSD: pf.conf,v 1.27 2004/03/02 20:13:55 cedric Exp $
#
# See pf.conf(5) and /usr/share/pf for syntax and examples.

#ext_if="ext0"
#int_if="int0"
ext_if="rl0"            #External intarface:
int_if="rl1"
#table <spamd> persist
#table <spamd-white> persist

#scrub in

#nat on $ext_if from !($ext_if) -> ($ext_if:0)
#rdr pass on $int_if proto tcp to port ftp -> 127.0.0.1 port 8021
#rdr pass on $ext_if proto tcp from <spamd> to port smtp \
#       -> 127.0.0.1 port spamd
#rdr pass on $ext_if proto tcp from !<spamd-white> to port smtp \
#       -> 127.0.0.1 port spamd
nat on rl0 from 192.168.7.1/16 to any -> 192.168.1.11

#block in
#pass out keep state
#pass in all
#pass out all

#pass quick on { lo $int_if }
#antispoof quick for { lo $int_if }

#pass in on $ext_if proto tcp to ($ext_if) port ssh keep state
#pass in on $ext_if proto tcp to ($ext_if) port > 49151 user proxy keep state
#pass in log on $ext_if proto tcp to ($ext_if) port smtp keep state
#pass out log on $ext_if proto tcp from ($ext_if) to port smtp keep state

#pass out log on $Ext_if all

проблема заключаеться в том что компы находящиеся за ним не могут использовать ftp кроме как в пассивном режиме.

Как разрешить ftp не в пассивном режиме. а то ни один каталог на ftp сервере создать нельзя.