Коннекты к серверу должны обрабатываться ДО НАТ-а.
Не буду извращаться, переделывая твой конфиг, а для примера щас попробую создать новый.... Навожу "кусок" /etc/rc.firewall с блоком правил для тебя:
[Nn][Aa][Tt])
oif="nfe0"
iif="rl0"
inet="192.168.1.0/24"
onet="xx.xx.226.0/23"
natip="xx.xx.227.101"
#NAT
${fwcmd} nat 1 config ip ${natip} unreg_only \
redirect_port tcp 192.168.1.100:3389 3389
# Stop spoofing
${fwcmd} add deny all from ${inet} to any in via ${oif}
${fwcmd} add deny all from ${onet} to any in via ${iif}
# Stop RFC1918 nets on the outside interface
${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif}
${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif}
# Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1,
# DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E)
# on the outside interface
${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif}
${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif}
${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif}
${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif}
${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif}
# Stop RFC1918 nets on the outside interface
${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif}
${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif}
# Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1,
# DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E)
# on the outside interface
${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif}
${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif}
${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif}
${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif}
${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif}
# NAT forwarding
${fwcmd} add nat 1 ip from ${inet} to any xmit ${oif}
${fwcmd} add nat 1 ip from any to ${natip} recv ${oif}
# Allow ICMP
${fwcmd} add allow icmp from any to any icmptypes 0,3,8,11
# Allow TCP through if setup succeeded
${fwcmd} add pass tcp from any to any established
# Allow setup
${fwcmd} add pass tcp from any to me 22 setup
${fwcmd} add pass tcp from any to me 25 setup
${fwcmd} add pass tcp from any to me 80 setup
# DNS
${fwcmd} add pass udp from any to me 53
${fwcmd} add pass udp from me 53 to any
# Allow my setup TCP connection
${fwcmd} add pass tcp from me to any setup
# Deny incoming
${fwcmd} add deny all from any to any via ${oif}
;;
При такой конфигурации должно все работать.
Сорри, не тестировал. Только набросал основные правила. Но, кажется, ошибки не допустил.
Кстати, у тебя ошибка в rc.conf.
Указывай не firewall_type, а firewall_script.
Пример:
firewall_enable="YES"
firewall_script="/etc/rc.firewall"
firewall_type="NAT"