################################################################################
#
# Configuration for PF firewall under FreeBSD.
#
# /etc/pf.conf
#
# More info: https://www.librobert.net/book/internet
#
################################################################################
#
# Copyright (c) 2019 Robert LA LAU < https://www.librobert.net/ >
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
#
# 3. Neither the name of the copyright holder nor the names of its contributors
#    may be used to endorse or promote products derived from this software
#    without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
################################################################################

interface = "em0"

tcp_ok = "{ 22 }"
udp_ok = "{ 53 }"

table <trusted> persist { }

table <martians> const { 0.0.0.0/8 10.0.0.0/8 \
  127.0.0.0/8 172.16.0.0/12 192.0.0.0/24 192.0.2.0/24 \
  192.168.0.0/16 198.18.0.0/15 198.51.100.0/24 \
  203.0.113.0/24 }

set skip on lo0

scrub in all

antispoof for $interface

anchor "f2b/*"

block in all
pass out all keep state

block drop in quick on $interface from <martians> to any
block drop out quick on $interface from any to <martians>

pass in quick on $interface from <trusted> to any

pass in proto tcp to $interface port 22

pass inet proto icmp icmp-type echoreq

pass proto tcp from any to $interface port $tcp_ok

pass proto udp from any to $interface port $udp_ok