ان‌پی‌اف

# Assigning IPv4-only addresses of the specified interfaces.
$ext_if = inet4(wm0)
$int_if = inet4(wm1)
# Efficient tables to store IP sets.
table <1> type hash file "/etc/npf_blacklist"
table <2> type tree dynamic
# Variables with the service names.
$services_tcp = { http, https, smtp, domain 9022 }
$services_udp = { domain, ntp }
$localnet = { 10.1.1.0/24 }
# Different forms of NAT are supported.
map $ext_if dynamic 10.1.1.0/24 -> $ext_if
map $ext_if dynamic 10.1.1.2 port 22 <- $ext_if port 9022
# NPF has various extensions which are supported via custom procedures.
procedure "log" {
	log: npflog0
}
## Grouping is mandatory in NPF.
# There must be a default group.
#group "external" on $ext_if {
	# Stateful passing of all outgoing traffic.
	pass stateful out final all

	block in final from <1>
	pass stateful in final family inet proto tcp to $ext_if port ssh apply "log"
	pass stateful in final proto tcp to $ext_if port $services_tcp
	pass stateful in final proto udp to $ext_if port $services_udp

	# Passive FTP and traceroute
	pass stateful in final proto tcp to $ext_if port 49151-65535
	pass stateful in final proto udp to $ext_if port 33434-33600
}

group "internal" on $int_if {
	# Ingress filtering as per RFC 2827.
	block in all
	pass in final from $localnet
	pass in final from <2>
	pass out final all
}

group default {
	pass final on lo0 all
	block all
}