# macros
int_if = "re0"
ext_if = "re1"
internal_net="10.0.0.0/8"
external_addr="69.30.132.109"

tcp_services = "{ 22, 80, 113 }"
icmp_types = "echoreq"

#priv_nets = "{ 127.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8 }"
priv_nets = "{ 127.0.0.0/8, 10.0.0.0/8 }"
# options
set block-policy return
set loginterface $ext_if
set skip on lo0

# scrub
scrub in all

# nat/rdr
#nat on $ext inet from 172.16.10.0/24 to any -> ($ext_if)
#nat on $ext_if from $int_if:network to any -> ($ext_if)
nat on $ext_if from $internal_net to any -> ($ext_if)
rdr on $ext_if proto tcp from any to $external_addr/32 port 1234 -> 10.0.0.0 port 5678
rdr on $int_if proto tcp from any to any port 21 -> 127.0.0.1  port 8021

# filter rules
block all

pass quick on lo0 all

block drop in  quick on $ext_if from $priv_nets to any
block drop out quick on $ext_if from any to $priv_nets

# allow access to tcp_services on external interface
pass in on $ext_if inet proto tcp from any to ($ext_if) \
   port $tcp_services flags S/SA keep state

# allow in FTP control port
pass in on $ext_if inet proto tcp from port 20 to ($ext_if) user proxy flags S/SA keep state

# allow in ping replies
pass in inet proto icmp all icmp-type $icmp_types keep state

# allow all traffic from internal network to internal interface
pass in  on $int_if from $int_if:network to any keep state
pass out on $int_if from any to $int_if:network keep state

# allow all traffic out via external interface
pass out on $ext_if proto tcp all modulate state flags S/SA
pass out on $ext_if proto { udp, icmp } all keep state