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      1 # $NetBSD: l2tp_gw-npf.conf,v 1.6 2016/02/06 20:19:28 riastradh Exp $
      2 #
      3 # ex0 - (internal) network interface
      4 #	192.0.2.254/24
      5 # hme0 - (external) connection to Peer
      6 #	198.51.100.142/24
      7 
      8 $int_if = "ex0"
      9 $ext_if = "hme0"
     10 
     11 $private_addr = { 10.0.0.0/8, 172.16.0.0/14, 192.168.0.0/16 }
     12 
     13 alg "icmp"
     14 
     15 #
     16 # NAT for all.
     17 #
     18 map $ext_if dynamic 192.0.2.0/24 -> inet4($ext_if)
     19 
     20 #table <1> type tree file "/etc/npf_problem_sites"
     21 
     22 procedure "log" {
     23 	log: npflog0
     24 }
     25 
     26 group "external" on $ext_if {
     27 	#
     28 	# Allow DHCP requests (even to reserved addresses).
     29 	#
     30 	pass out final proto udp from any port bootpc to any port bootps
     31 	pass in final proto udp from any port bootps to any port bootpc
     32 	pass in final proto udp from any port bootps to 255.255.255.255 port bootpc
     33 	#
     34 	# Allow DNS queries
     35 	#
     36 	pass stateful out final proto udp to any port domain
     37 
     38 	# Problem sites.
     39 	#block in final from <1> apply "log"
     40 
     41 	#
     42 	# Block IANA-reserved addresses from entering or exiting
     43 	#
     44 	block in final from $private_addr apply "log"
     45 	block out final to $private_addr apply "log"
     46 	#
     47 	pass stateful out final proto tcp all
     48 	pass stateful out final proto udp all
     49 	pass stateful out final proto icmp all
     50 	pass stateful out final proto ipv6-icmp all
     51 
     52 	block in final proto tcp to 192.0.2.255 apply "log"
     53 
     54 	#
     55 	# Prevent IP spoofing attacks on the firewall.
     56 	#
     57 	block in final from 127.0.0.1 apply "log"
     58 
     59 	#
     60 	# L2TP/IPSEC-NAT-T Tunnels.
     61 	#
     62 	pass in final proto esp from any to inet4($ext_if)
     63 	pass out final proto esp from inet4($ext_if) to any
     64 	pass stateful in final from any to inet4($ext_if) port "ipsec-nat-t"
     65 	pass stateful in final from any to inet4($ext_if) port l2tp
     66 
     67 	#
     68 	# Pass multicast.
     69 	# IGMP uses 224.0.0.1.
     70 	#
     71 	pass in final proto igmp all
     72 	pass in final from any to 224.0.0.0/4
     73 
     74 	#
     75 	# Pass established connections.
     76 	#
     77 	pass in final proto tcp flags A/A all
     78 	pass in final proto tcp flags R/R all
     79 	#
     80 	# VNC
     81 	#
     82 	pass in final proto tcp from any to any port 5500
     83 
     84 	#
     85 	# Web servers
     86 	#
     87 	#pass in final proto tcp from any to <A>/<M> port http
     88 
     89 	#
     90 	# Services on localhost.
     91 	#
     92 	#pass in final proto udp from any port ntp
     93 	#pass in final to any port imap
     94 	#pass in final to any port domain
     95 	#pass in final proto tcp to any port smtp
     96 	#pass in final proto tcp to any port auth
     97 	#pass in final proto tcp to any port ssh
     98 	#pass in final proto tcp to any port bgp
     99 	#pass in final proto tcp to any port ftp
    100 	#pass in final proto tcp to any port "ftp-data"
    101 	#pass in final proto udp to any port isakmp
    102 	#pass in final proto udp to any port 8001
    103 	#pass in final proto tcp to inet4($ext_if) port www
    104 
    105 	#
    106 	# Handle traceroute gracefully for up-to 30 hops away.
    107 	# FIXME: port-unr for ICMP is not yet supported.
    108 	#
    109 	block return-icmp in final proto udp to any port 33433-33524 apply "log"
    110 
    111 	#
    112 	# Only allow selected ICMP types.
    113 	#
    114 	pass in final proto icmp icmp-type echo all
    115 	pass in final proto icmp icmp-type timxceed all
    116 	pass in final proto icmp icmp-type unreach all
    117 	pass in final proto icmp icmp-type echoreply all
    118 	pass in final proto icmp icmp-type sourcequench all
    119 	pass in final proto icmp icmp-type paramprob all
    120 	pass in final proto ipv6-icmp all
    121 
    122 	#
    123 	# Send back a reset for new connections on tcp.
    124 	#
    125 	block return-rst in final proto tcp flags S/SA all apply "log"
    126 }
    127 
    128 group "internal" on $int_if {
    129 	# Pass everything to internal networks,
    130 	# should be ok, because we are nat'ed.
    131 	pass final all
    132 }
    133 
    134 group default {
    135 	# Loopback interface should allows packets to traverse it.
    136 	pass final on lo0 all
    137 	# For one L2TP tunnel, needs interface pre-created, post-destroyed
    138 	pass final on ppp0 all
    139 
    140 	#
    141 	# Block everything by default.
    142 	#
    143 	block final all apply "log"
    144 }
    145