# $OpenBSD: faq-example1,v 1.2 2003/08/06 16:04:45 henning Exp $

#
# Firewall for Home or Small Office
# http://www.openbsd.org/faq/pf/example1.html
#


# macros
int_if = "fxp0"
ext_if = "ep0"

tcp_services = "{ 22, 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 }"
        
# options
set block-policy return
set loginterface $ext_if

# scrub
scrub in all

# nat/rdr
nat on $ext_if from $int_if:network to any -> ($ext_if)
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

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

pass in inet proto icmp all icmp-type $icmp_types keep state

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

pass out on $ext_if proto tcp all modulate state flags S/SA
pass out on $ext_if proto { udp, icmp } all keep state